Related
How do you get the rendered height of an element?
Let's say you have a <div> element with some content inside. This content inside is going to stretch the height of the <div>. How do you get the "rendered" height when you haven't explicitly set the height. Obviously, I tried:
var h = document.getElementById('someDiv').style.height;
Is there a trick for doing this? I am using jQuery if that helps.
Try one of:
var h = document.getElementById('someDiv').clientHeight;
var h = document.getElementById('someDiv').offsetHeight;
var h = document.getElementById('someDiv').scrollHeight;
clientHeight includes the height and vertical padding.
offsetHeight includes the height, vertical padding, and vertical borders.
scrollHeight includes the height of the contained document (would be greater than just height in case of scrolling), vertical padding, and vertical borders.
It should just be
$('#someDiv').height();
with jQuery. This retrieves the height of the first item in the wrapped set as a number.
Trying to use
.style.height
only works if you have set the property in the first place. Not very useful!
NON JQUERY since there were a bunch of links using elem.style.height in the top of these answers...
INNER HEIGHT:
https://developer.mozilla.org/en-US/docs/Web/API/Element.clientHeight
document.getElementById(id_attribute_value).clientHeight;
OUTER HEIGHT:
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.offsetHeight
document.getElementById(id_attribute_value).offsetHeight;
Or one of my favorite references: http://youmightnotneedjquery.com/
I use this to get the height of an element (returns float):
document.getElementById('someDiv').getBoundingClientRect().height
It also works when you use the virtual DOM. I use it in Vue like this:
this.$refs['some-ref'].getBoundingClientRect().height
For a Vue component:
this.$refs['some-ref'].$el.getBoundingClientRect().height
You can use .outerHeight() for this purpose.
It will give you full rendered height of the element. Also, you don't need to set any css-height of the element. For precaution you can keep its height auto so it can be rendered as per content's height.
//if you need height of div excluding margin/padding/border
$('#someDiv').height();
//if you need height of div with padding but without border + margin
$('#someDiv').innerHeight();
// if you need height of div including padding and border
$('#someDiv').outerHeight();
//and at last for including border + margin + padding, can use
$('#someDiv').outerHeight(true);
For a clear view of these function you can go for jQuery's site or a detailed post here.
it will clear the difference between .height() / innerHeight() / outerHeight()
style = window.getComputedStyle(your_element);
then simply: style.height
Definitely use
$('#someDiv').height() // to read it
or
$('#someDiv').height(newHeight) // to set it
I'm posting this as an additional answer because theres a couple important things I just learnt.
I almost fell into the trap just now of using offsetHeight. This is what happened :
I used the good old trick of using a debugger to 'watch' what properties my element has
I saw which one has a value around the value I was expecting
It was offsetHeight - so I used that.
Then i realized it didnt work with a hidden DIV
I tried hiding after calculating maxHeight but that looked clumsy - got in a mess.
I did a search - discovered jQuery.height() - and used it
found out height() works even on hidden elements
just for fun I checked the jQuery implementation of height/width
Here's just a portion of it :
Math.max(
Math.max(document.body["scroll" + name], document.documentElement["scroll" + name]),
Math.max(document.body["offset" + name], document.documentElement["offset" + name])
)
Yup it looks at BOTH scroll and offset. If that fails it looks even further, taking into account browser and css compatibility issues. In other words STUFF I DONT CARE ABOUT - or want to.
But I dont have to. Thanks jQuery!
Moral of the story : if jQuery has a method for something its probably for a good reason, likely related to compatibilty.
If you haven't read through the jQuery list of methods recently I suggest you take a look.
I think the best way to do this in 2020 is to use vanilla js and getBoundingClientRect().height;
Here's an example
let div = document.querySelector('div');
let divHeight = div.getBoundingClientRect().height;
console.log(`Div Height: ${divHeight}`);
<div>
How high am I? 🥴
</div>
On top of getting height this way, we also have access to a bunch of other stuff about the div.
let div = document.querySelector('div');
let divInfo = div.getBoundingClientRect();
console.log(divInfo);
<div>What else am I? 🥴</div>
I made a simple code that doesn't even need JQuery and probably gonna help some people.
It gets the total height of 'ID1' after loaded and use it on 'ID2'
function anyName(){
var varname=document.getElementById('ID1').offsetHeight;
document.getElementById('ID2').style.height=varname+'px';
}
Then just set the body to load it
<body onload='anyName()'>
document.querySelector('.project_list_div').offsetHeight;
Hm we can get the Element geometry...
var geometry;
geometry={};
var element=document.getElementById(#ibims);
var rect = element.getBoundingClientRect();
this.geometry.top=rect.top;
this.geometry.right=rect.right;
this.geometry.bottom=rect.bottom;
this.geometry.left=rect.left;
this.geometry.height=this.geometry.bottom-this.geometry.top;
this.geometry.width=this.geometry.right-this.geometry.left;
console.log(this.geometry);
How about this plain JS ?
So is this the answer?
"If you need to calculate something but not show it, set the element to visibility:hidden and position:absolute, add it to the DOM tree, get the offsetHeight, and remove it. (That's what the prototype library does behind the lines last time I checked)."
I have the same problem on a number of elements. There is no jQuery or Prototype to be used on the site but I'm all in favor of borrowing the technique if it works. As an example of some things that failed to work, followed by what did, I have the following code:
// Layout Height Get
function fnElementHeightMaxGet(DoScroll, DoBase, elementPassed, elementHeightDefault)
{
var DoOffset = true;
if (!elementPassed) { return 0; }
if (!elementPassed.style) { return 0; }
var thisHeight = 0;
var heightBase = parseInt(elementPassed.style.height);
var heightOffset = parseInt(elementPassed.offsetHeight);
var heightScroll = parseInt(elementPassed.scrollHeight);
var heightClient = parseInt(elementPassed.clientHeight);
var heightNode = 0;
var heightRects = 0;
//
if (DoBase) {
if (heightBase > thisHeight) { thisHeight = heightBase; }
}
if (DoOffset) {
if (heightOffset > thisHeight) { thisHeight = heightOffset; }
}
if (DoScroll) {
if (heightScroll > thisHeight) { thisHeight = heightScroll; }
}
//
if (thisHeight == 0) { thisHeight = heightClient; }
//
if (thisHeight == 0) {
// Dom Add:
// all else failed so use the protype approach...
var elBodyTempContainer = document.getElementById('BodyTempContainer');
elBodyTempContainer.appendChild(elementPassed);
heightNode = elBodyTempContainer.childNodes[0].offsetHeight;
elBodyTempContainer.removeChild(elementPassed);
if (heightNode > thisHeight) { thisHeight = heightNode; }
//
// Bounding Rect:
// Or this approach...
var clientRects = elementPassed.getClientRects();
heightRects = clientRects.height;
if (heightRects > thisHeight) { thisHeight = heightRects; }
}
//
// Default height not appropriate here
// if (thisHeight == 0) { thisHeight = elementHeightDefault; }
if (thisHeight > 3000) {
// ERROR
thisHeight = 3000;
}
return thisHeight;
}
which basically tries anything and everything only to get a zero result. ClientHeight with no affect. With the problem elements I typically get NaN in the Base and zero in the Offset and Scroll heights. I then tried the Add DOM solution and clientRects to see if it works here.
29 Jun 2011,
I did indeed update the code to try both adding to DOM and clientHeight with better results than I expected.
1) clientHeight was also 0.
2) Dom actually gave me a height which was great.
3) ClientRects returns a result almost identical to the DOM technique.
Because the elements added are fluid in nature, when they are added to an otherwise empty DOM Temp element they are rendered according to the width of that container. This get weird, because that is 30px shorter than it eventually ends up.
I added a few snapshots to illustrate how the height is calculated differently.
The height differences are obvious. I could certainly add absolute positioning and hidden but I am sure that will have no effect. I continued to be convinced this would not work!
(I digress further) The height comes out (renders) lower than the true rendered height. This could be addressed by setting the width of the DOM Temp element to match the existing parent and could be done fairly accurately in theory. I also do not know what would result from removing them and adding them back into their existing location. As they arrived through an innerHTML technique I will be looking using this different approach.
* HOWEVER * None of that was necessary. In fact it worked as advertised and returned the correct height!!!
When I was able to get the menus visible again amazingly DOM had returned the correct height per the fluid layout at the top of the page (279px). The above code also uses getClientRects which return 280px.
This is illustrated in the following snapshot (taken from Chrome once working.)
Now I have noooooo idea why that prototype trick works, but it seems to. Alternatively, getClientRects also works.
I suspect the cause of all this trouble with these particular elements was the use of innerHTML instead of appendChild, but that is pure speculation at this point.
offsetHeight, usually.
If you need to calculate something but not show it, set the element to visibility:hidden and position:absolute, add it to the DOM tree, get the offsetHeight, and remove it. (That's what the prototype library does behind the scenes last time I checked).
Sometimes offsetHeight will return zero because the element you've created has not been rendered in the Dom yet. I wrote this function for such circumstances:
function getHeight(element)
{
var e = element.cloneNode(true);
e.style.visibility = "hidden";
document.body.appendChild(e);
var height = e.offsetHeight + 0;
document.body.removeChild(e);
e.style.visibility = "visible";
return height;
}
If you are using jQuery already, your best bet is .outerHeight() or .height(), as has been stated.
Without jQuery, you can check the box-sizing in use and add up various paddings + borders + clientHeight, or you can use getComputedStyle:
var h = getComputedStyle(document.getElementById('someDiv')).height;
h will now be a string like a "53.825px".
And I can't find the reference, but I think I heard getComputedStyle() can be expensive, so it's probably not something you want to call on each window.onscroll event (but then, neither is jQuery's height()).
With MooTools:
$('someDiv').getSize().y
If i understood your question correctly, then maybe something like this would help:
function testDistance(node1, node2) {
/* get top position of node 1 */
let n1Pos = node1.offsetTop;
/* get height of node 1 */
let n1Height = node1.clientHeight;
/* get top position of node 2 */
let n2Pos = node2.offsetTop;
/* get height of node 2 */
let n2Height = node2.clientHeight;
/* add height of both nodes */
let heightTogether = n1Height + n2Height;
/* calculate distance from top of node 1 to bottom of node 2 */
let actualDistance = (n2Pos + n2Height) - n1Pos;
/* if the distance between top of node 1 and bottom of node 2
is bigger than their heights combined, than there is something between them */
if (actualDistance > heightTogether) {
/* do something here if they are not together */
console.log('they are not together');
} else {
/* do something here if they are together */
console.log('together');
}
}
Have you set the height in the css specifically? If you haven't you need to use offsetHeight; rather than height
var h = document.getElementById('someDiv').style.offsetHeight;
How do you get the rendered height of an element?
Let's say you have a <div> element with some content inside. This content inside is going to stretch the height of the <div>. How do you get the "rendered" height when you haven't explicitly set the height. Obviously, I tried:
var h = document.getElementById('someDiv').style.height;
Is there a trick for doing this? I am using jQuery if that helps.
Try one of:
var h = document.getElementById('someDiv').clientHeight;
var h = document.getElementById('someDiv').offsetHeight;
var h = document.getElementById('someDiv').scrollHeight;
clientHeight includes the height and vertical padding.
offsetHeight includes the height, vertical padding, and vertical borders.
scrollHeight includes the height of the contained document (would be greater than just height in case of scrolling), vertical padding, and vertical borders.
It should just be
$('#someDiv').height();
with jQuery. This retrieves the height of the first item in the wrapped set as a number.
Trying to use
.style.height
only works if you have set the property in the first place. Not very useful!
NON JQUERY since there were a bunch of links using elem.style.height in the top of these answers...
INNER HEIGHT:
https://developer.mozilla.org/en-US/docs/Web/API/Element.clientHeight
document.getElementById(id_attribute_value).clientHeight;
OUTER HEIGHT:
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.offsetHeight
document.getElementById(id_attribute_value).offsetHeight;
Or one of my favorite references: http://youmightnotneedjquery.com/
I use this to get the height of an element (returns float):
document.getElementById('someDiv').getBoundingClientRect().height
It also works when you use the virtual DOM. I use it in Vue like this:
this.$refs['some-ref'].getBoundingClientRect().height
For a Vue component:
this.$refs['some-ref'].$el.getBoundingClientRect().height
You can use .outerHeight() for this purpose.
It will give you full rendered height of the element. Also, you don't need to set any css-height of the element. For precaution you can keep its height auto so it can be rendered as per content's height.
//if you need height of div excluding margin/padding/border
$('#someDiv').height();
//if you need height of div with padding but without border + margin
$('#someDiv').innerHeight();
// if you need height of div including padding and border
$('#someDiv').outerHeight();
//and at last for including border + margin + padding, can use
$('#someDiv').outerHeight(true);
For a clear view of these function you can go for jQuery's site or a detailed post here.
it will clear the difference between .height() / innerHeight() / outerHeight()
style = window.getComputedStyle(your_element);
then simply: style.height
Definitely use
$('#someDiv').height() // to read it
or
$('#someDiv').height(newHeight) // to set it
I'm posting this as an additional answer because theres a couple important things I just learnt.
I almost fell into the trap just now of using offsetHeight. This is what happened :
I used the good old trick of using a debugger to 'watch' what properties my element has
I saw which one has a value around the value I was expecting
It was offsetHeight - so I used that.
Then i realized it didnt work with a hidden DIV
I tried hiding after calculating maxHeight but that looked clumsy - got in a mess.
I did a search - discovered jQuery.height() - and used it
found out height() works even on hidden elements
just for fun I checked the jQuery implementation of height/width
Here's just a portion of it :
Math.max(
Math.max(document.body["scroll" + name], document.documentElement["scroll" + name]),
Math.max(document.body["offset" + name], document.documentElement["offset" + name])
)
Yup it looks at BOTH scroll and offset. If that fails it looks even further, taking into account browser and css compatibility issues. In other words STUFF I DONT CARE ABOUT - or want to.
But I dont have to. Thanks jQuery!
Moral of the story : if jQuery has a method for something its probably for a good reason, likely related to compatibilty.
If you haven't read through the jQuery list of methods recently I suggest you take a look.
I think the best way to do this in 2020 is to use vanilla js and getBoundingClientRect().height;
Here's an example
let div = document.querySelector('div');
let divHeight = div.getBoundingClientRect().height;
console.log(`Div Height: ${divHeight}`);
<div>
How high am I? 🥴
</div>
On top of getting height this way, we also have access to a bunch of other stuff about the div.
let div = document.querySelector('div');
let divInfo = div.getBoundingClientRect();
console.log(divInfo);
<div>What else am I? 🥴</div>
I made a simple code that doesn't even need JQuery and probably gonna help some people.
It gets the total height of 'ID1' after loaded and use it on 'ID2'
function anyName(){
var varname=document.getElementById('ID1').offsetHeight;
document.getElementById('ID2').style.height=varname+'px';
}
Then just set the body to load it
<body onload='anyName()'>
document.querySelector('.project_list_div').offsetHeight;
Hm we can get the Element geometry...
var geometry;
geometry={};
var element=document.getElementById(#ibims);
var rect = element.getBoundingClientRect();
this.geometry.top=rect.top;
this.geometry.right=rect.right;
this.geometry.bottom=rect.bottom;
this.geometry.left=rect.left;
this.geometry.height=this.geometry.bottom-this.geometry.top;
this.geometry.width=this.geometry.right-this.geometry.left;
console.log(this.geometry);
How about this plain JS ?
So is this the answer?
"If you need to calculate something but not show it, set the element to visibility:hidden and position:absolute, add it to the DOM tree, get the offsetHeight, and remove it. (That's what the prototype library does behind the lines last time I checked)."
I have the same problem on a number of elements. There is no jQuery or Prototype to be used on the site but I'm all in favor of borrowing the technique if it works. As an example of some things that failed to work, followed by what did, I have the following code:
// Layout Height Get
function fnElementHeightMaxGet(DoScroll, DoBase, elementPassed, elementHeightDefault)
{
var DoOffset = true;
if (!elementPassed) { return 0; }
if (!elementPassed.style) { return 0; }
var thisHeight = 0;
var heightBase = parseInt(elementPassed.style.height);
var heightOffset = parseInt(elementPassed.offsetHeight);
var heightScroll = parseInt(elementPassed.scrollHeight);
var heightClient = parseInt(elementPassed.clientHeight);
var heightNode = 0;
var heightRects = 0;
//
if (DoBase) {
if (heightBase > thisHeight) { thisHeight = heightBase; }
}
if (DoOffset) {
if (heightOffset > thisHeight) { thisHeight = heightOffset; }
}
if (DoScroll) {
if (heightScroll > thisHeight) { thisHeight = heightScroll; }
}
//
if (thisHeight == 0) { thisHeight = heightClient; }
//
if (thisHeight == 0) {
// Dom Add:
// all else failed so use the protype approach...
var elBodyTempContainer = document.getElementById('BodyTempContainer');
elBodyTempContainer.appendChild(elementPassed);
heightNode = elBodyTempContainer.childNodes[0].offsetHeight;
elBodyTempContainer.removeChild(elementPassed);
if (heightNode > thisHeight) { thisHeight = heightNode; }
//
// Bounding Rect:
// Or this approach...
var clientRects = elementPassed.getClientRects();
heightRects = clientRects.height;
if (heightRects > thisHeight) { thisHeight = heightRects; }
}
//
// Default height not appropriate here
// if (thisHeight == 0) { thisHeight = elementHeightDefault; }
if (thisHeight > 3000) {
// ERROR
thisHeight = 3000;
}
return thisHeight;
}
which basically tries anything and everything only to get a zero result. ClientHeight with no affect. With the problem elements I typically get NaN in the Base and zero in the Offset and Scroll heights. I then tried the Add DOM solution and clientRects to see if it works here.
29 Jun 2011,
I did indeed update the code to try both adding to DOM and clientHeight with better results than I expected.
1) clientHeight was also 0.
2) Dom actually gave me a height which was great.
3) ClientRects returns a result almost identical to the DOM technique.
Because the elements added are fluid in nature, when they are added to an otherwise empty DOM Temp element they are rendered according to the width of that container. This get weird, because that is 30px shorter than it eventually ends up.
I added a few snapshots to illustrate how the height is calculated differently.
The height differences are obvious. I could certainly add absolute positioning and hidden but I am sure that will have no effect. I continued to be convinced this would not work!
(I digress further) The height comes out (renders) lower than the true rendered height. This could be addressed by setting the width of the DOM Temp element to match the existing parent and could be done fairly accurately in theory. I also do not know what would result from removing them and adding them back into their existing location. As they arrived through an innerHTML technique I will be looking using this different approach.
* HOWEVER * None of that was necessary. In fact it worked as advertised and returned the correct height!!!
When I was able to get the menus visible again amazingly DOM had returned the correct height per the fluid layout at the top of the page (279px). The above code also uses getClientRects which return 280px.
This is illustrated in the following snapshot (taken from Chrome once working.)
Now I have noooooo idea why that prototype trick works, but it seems to. Alternatively, getClientRects also works.
I suspect the cause of all this trouble with these particular elements was the use of innerHTML instead of appendChild, but that is pure speculation at this point.
offsetHeight, usually.
If you need to calculate something but not show it, set the element to visibility:hidden and position:absolute, add it to the DOM tree, get the offsetHeight, and remove it. (That's what the prototype library does behind the scenes last time I checked).
Sometimes offsetHeight will return zero because the element you've created has not been rendered in the Dom yet. I wrote this function for such circumstances:
function getHeight(element)
{
var e = element.cloneNode(true);
e.style.visibility = "hidden";
document.body.appendChild(e);
var height = e.offsetHeight + 0;
document.body.removeChild(e);
e.style.visibility = "visible";
return height;
}
If you are using jQuery already, your best bet is .outerHeight() or .height(), as has been stated.
Without jQuery, you can check the box-sizing in use and add up various paddings + borders + clientHeight, or you can use getComputedStyle:
var h = getComputedStyle(document.getElementById('someDiv')).height;
h will now be a string like a "53.825px".
And I can't find the reference, but I think I heard getComputedStyle() can be expensive, so it's probably not something you want to call on each window.onscroll event (but then, neither is jQuery's height()).
With MooTools:
$('someDiv').getSize().y
If i understood your question correctly, then maybe something like this would help:
function testDistance(node1, node2) {
/* get top position of node 1 */
let n1Pos = node1.offsetTop;
/* get height of node 1 */
let n1Height = node1.clientHeight;
/* get top position of node 2 */
let n2Pos = node2.offsetTop;
/* get height of node 2 */
let n2Height = node2.clientHeight;
/* add height of both nodes */
let heightTogether = n1Height + n2Height;
/* calculate distance from top of node 1 to bottom of node 2 */
let actualDistance = (n2Pos + n2Height) - n1Pos;
/* if the distance between top of node 1 and bottom of node 2
is bigger than their heights combined, than there is something between them */
if (actualDistance > heightTogether) {
/* do something here if they are not together */
console.log('they are not together');
} else {
/* do something here if they are together */
console.log('together');
}
}
Have you set the height in the css specifically? If you haven't you need to use offsetHeight; rather than height
var h = document.getElementById('someDiv').style.offsetHeight;
I just saw something very interesting in vk.com
Basically in profile page the right column is changing its width when the left column is gone of the view.
Example : http://vk.com/durov
Just scroll down a little bit to see it.
Every element in the DOM defines certain spatial offset properties that can be accessed from JavaScript, them being offsetTop, offsetLeft etc. which give you the value how much offset it has from its parent. You can also access the parent in question with a while loop which simply assigns the next parent until none are left ( you can add their offsets to the variables of the original offset to gain the "true" (x,y) offset) and the while loop exists when there are no more parent elements.
Then you do some simple logic to check whether or not it is located within the viewport (hint - use the page offset and width/height properties of the window object). Is this enough to go on or do you need a code sample?
You could do some hacks if you know where exactly your element will appear and its height (width is really of no consequence here), but that's a brute force approach. Simply checking the page Y offset and height against the predetermined "maxY" of the element you're trying to get offscreen to display a certain div to the right (like in the example given).
ADDENDUM: (Even more to the point)
This checks whether ANY part of the element is visible in the viewport:
function isVisibleInViewport(elem)
{
var y = elem.offsetTop;
var height = elem.offsetHeight;
while ( elem = elem.offsetParent )
y += elem.offsetTop;
var maxHeight = y + height;
var isVisible = ( y < ( window.pageYOffset + window.innerHeight ) ) && ( maxHeight >= window.pageYOffset );
return isVisible;
}
I tried writing it with clarity in mind. You can shorten it further if you wish. Even expand it to include logic if you wish to move to the side (x-axis, offsetLeft variable). And changes to your logic ought to be minimal if you want to check whether it's completely within view ( can't see a reason though).
My example usage
The logic to govern when to call this function goes beyond the scope of this, I hope you have some method in mind. My example:
function check()
{
var canvas = document.getElementById("webGlExperiments");
if(isVisibleInViewport(canvas))
document.getElementById("test").innerHTML = "It is!";
else
document.getElementById("test").innerHTML = "It is not!";
}
And then add an event listener to check for scrolls:
window.addEventListener("scroll", check, false);
For my example, you'll also need another element like a canvas with the id webGlExperiments, change it to something that suits you and your problem. This is the div in question I used in my test which you can adapt for yourself:
<div id="test" style="margin-top:100px;">Testing, testing!</div>
in javascript can I make sure that my large div scroll vertically
only in chunks of (let's say) 16 pixels
In java, those are called 'units of increment'.
I can't find anything similar in javascript:
I want to ensure that a certain area (div) when partially scrolled is always a multiple of 16 the view.
That allows me to do tricks with background images and others.
thanks
var lastScroll = 0;
$('div').scroll(function(){
var el = $(this),
scroll = el.scrollTop(),
round = lastScroll < scroll ? Math.ceil : Math.floor;
lastScroll = round(scroll/16) * 16;
el.scrollTop(lastScroll);
});
http://jsfiddle.net/m9DQR/2/
Ensures scrolls are done in multiples of 16 pixels. You can easily extend this to be a plugin that allows for a variable amount (not a fixed, magical 16).
Yes, this is possible, but it will require using javascript to capture the scroll event and then manipulate it. This script (sorry jQuery is what I had) and overrides the scroll event. It then replaces it with the exact same scroll distance. You could perform your own math to adjust the value of scrollTo. We have to check both mousewheel and DOMMouseScroll events because the first is not supported by FF. This doesn't seem to apply in your case, but a user may have the number of lines to scroll set to something other than the default three. So the if statement calculates the distance. I left it in there though in case other people stumble on this question and it is important to them though.
$('body').bind('mousewheel DOMMouseScroll', function(e) {
var scrollTo = null;
if (e.type == 'mousewheel') {
scrollTo = (e.wheelDelta * -1);
}
else if (e.type == 'DOMMouseScroll') {
scrollTo = 40 * e.detail;
}
//adjust value of scrollTo here if you like.
scrollTo = 16;
if (scrollTo) {
e.preventDefault();
$(this).scrollTop(scrollTo + $(this).scrollTop());
}
});
Coming from another programming language I also found JavaScript difficult when dealing with UI. In your case I would just set a handler to the event onscroll and query the position of the div relative to the scroll position. Return false whenever position of div is not divisible by 16px and create a counter to allow reposition after another 16px is scrolled.
Is it possible to get the mouse position with JavaScript after page loads without any mouse movement event (without moving the mouse)?
Real answer: No, it's not possible.
OK, I have just thought of a way. Overlay your page with a div that covers the whole document. Inside that, create (say) 2,000 x 2,000 <a> elements (so that the :hover pseudo-class will work in IE 6, see), each 1 pixel in size. Create a CSS :hover rule for those <a> elements that changes a property (let's say font-family). In your load handler, cycle through each of the 4 million <a> elements, checking currentStyle / getComputedStyle() until you find the one with the hover font. Extrapolate back from this element to get the co-ordinates within the document.
N.B. DON'T DO THIS.
Edit 2020: This does not work any more. It seems so, that the browser vendors patched this out. Because the most browsers rely on chromium, it might be in its core.
Old answer:
You can also hook mouseenter (this event is fired after page reload, when the mousecursor is inside the page). Extending Corrupted's code should do the trick:
var x = null;
var y = null;
document.addEventListener('mousemove', onMouseUpdate, false);
document.addEventListener('mouseenter', onMouseUpdate, false);
function onMouseUpdate(e) {
x = e.pageX;
y = e.pageY;
console.log(x, y);
}
function getMouseX() {
return x;
}
function getMouseY() {
return y;
}
You can also set x and y to null on mouseleave-event. So you can check if the user is on your page with it's cursor.
What you can do is create variables for the x and y coordinates of your cursor, update them whenever the mouse moves and call a function on an interval to do what you need with the stored position.
The downside to this of course is that at least one initial movement of the mouse is required to have it work. As long as the cursor updates its position at least once, we are able to find its position regardless of whether it moves again.
var cursor_x = -1;
var cursor_y = -1;
document.onmousemove = function(event)
{
cursor_x = event.pageX;
cursor_y = event.pageY;
}
setInterval(check_cursor, 1000);
function check_cursor(){console.log('Cursor at: '+cursor_x+', '+cursor_y);}
The preceding code updates once a second with a message of where your cursor is.
#Tim Down's answer is not performant if you render 2,000 x 2,000 <a> elements:
OK, I have just thought of a way. Overlay your page with a div that
covers the whole document. Inside that, create (say) 2,000 x 2,000
elements (so that the :hover pseudo-class will work in IE 6, see),
each 1 pixel in size. Create a CSS :hover rule for those elements
that changes a property (let's say font-family). In your load handler,
cycle through each of the 4 million elements, checking
currentStyle / getComputedStyle() until you find the one with the
hover font. Extrapolate back from this element to get the co-ordinates
within the document.
N.B. DON'T DO THIS.
But you don't have to render 4 million elements at once, instead use binary search. Just use 4 <a> elements instead:
Step 1: Consider the whole screen as the starting search area
Step 2: Split the search area into 2 x 2 = 4 rectangle <a> elements
Step 3: Using the getComputedStyle() function determine in which rectangle mouse hovers
Step 4: Reduce the search area to that rectangle and repeat from step 2.
This way you would need to repeat these steps max 11 times, considering your screen is not wider than 2048px.
So you will generate max 11 x 4 = 44 <a> elements.
If you don't need to determine the mouse position exactly to a pixel, but say 10px precision is OK. You would repeat the steps at most 8 times, so you would need to draw max 8 x 4 = 32 <a> elements.
Also generating and then destroying the <a> elements is not performat as DOM is generally slow. Instead, you can just reuse the initial 4 <a> elements and just adjust their top, left, width and height as you loop through steps.
Now, creating 4 <a> is an overkill as well. Instead, you can reuse the same one <a> element for when testing for getComputedStyle() in each rectangle. So, instead of splitting the search area into 2 x 2 <a> elements just reuse a single <a> element by moving it with top and left style properties.
So, all you need is a single <a> element change its width and height max 11 times, and change its top and left max 44 times and you will have the exact mouse position.
You could try something similar to what Tim Down suggested - but instead of having elements for each pixel on the screen, create just 2-4 elements (boxes), and change their location, width, height dynamically to divide the yet possible locations on screen by 2-4 recursively, thus finding the mouse real location quickly.
For example - first elements take right and left half of screen, afterwards the upper and lower half. By now we already know in which quarter of screen the mouse is located, are able to repeat - discover which quarter of this space...
Here's my solution. It exports window.currentMouseX and window.currentMouseY properties you can use anywhere. It uses the position of a hovered element (if any) initially and afterwards listens to mouse movements to set the correct values.
(function () {
window.currentMouseX = 0;
window.currentMouseY = 0;
// Guess the initial mouse position approximately if possible:
var hoveredElement = document.querySelectorAll(':hover');
hoveredElement = hoveredElement[hoveredElement.length - 1]; // Get the most specific hovered element
if (hoveredElement != null) {
var rect = hoveredElement.getBoundingClientRect();
// Set the values from hovered element's position
window.currentMouseX = window.scrollX + rect.x;
window.currentMouseY = window.scrollY + rect.y;
}
// Listen for mouse movements to set the correct values
window.addEventListener('mousemove', function (e) {
window.currentMouseX = e.pageX;
window.currentMouseY = e.pageY;
}, /*useCapture=*/true);
}())
Composr CMS Source: https://github.com/ocproducts/composr/commit/a851c19f925be20bc16bfe016be42924989f262e#diff-b162dc9c35a97618a96748639ff41251R1202
The most simple solution but not 100% accurate
$(':hover').last().offset()
Result: {top: 148, left: 62.5}
The result depend on the nearest element size and return undefined when user switched the tab
Yes, It's possible.
If you add "mouseover" event to the document it will fire instantly and you can get the mouse position, of course if mouse pointer was over the document.
document.addEventListener('mouseover', setInitialMousePos, false);
function setInitialMousePos( event ) {
console.log( event.clientX, event.clientY);
document.removeEventListener('mouseover', setInitialMousePos, false);
}
Previously it was possible to read mouse position through window.event but it's deprecated now.
var x = 0;
var y = 0;
document.addEventListener('mousemove', onMouseMove, false)
function onMouseMove(e){
x = e.clientX;
y = e.clientY;
}
function getMouseX() {
return x;
}
function getMouseY() {
return y;
}
I implemented a horizontal/vertical search, (first make a div full of vertical line links arranged horizontally, then make a div full of horizontal line links arranged vertically, and simply see which one has the hover state) like Tim Down's idea above, and it works pretty fast. Sadly, does not work on Chrome 32 on KDE.
jsfiddle.net/5XzeE/4/
You do not have to move the mouse to get the cursor's location. The location is also reported on events other than mousemove. Here's a click-event as an example:
document.body.addEventListener('click',function(e)
{
console.log("cursor-location: " + e.clientX + ',' + e.clientY);
});
Riffing on #SuperNova's answer, here's an approach using ES6 classes that keeps the context for this correct in your callback:
class Mouse {
constructor() {
this.x = 0;
this.y = 0;
this.callbacks = {
mouseenter: [],
mousemove: [],
};
}
get xPos() {
return this.x;
}
get yPos() {
return this.y;
}
get position() {
return `${this.x},${this.y}`;
}
addListener(type, callback) {
document.addEventListener(type, this); // Pass `this` as the second arg to keep the context correct
this.callbacks[type].push(callback);
}
// `handleEvent` is part of the browser's `EventListener` API.
// https://developer.mozilla.org/en-US/docs/Web/API/EventListener/handleEvent
handleEvent(event) {
const isMousemove = event.type === 'mousemove';
const isMouseenter = event.type === 'mouseenter';
if (isMousemove || isMouseenter) {
this.x = event.pageX;
this.y = event.pageY;
}
this.callbacks[event.type].forEach((callback) => {
callback();
});
}
}
const mouse = new Mouse();
mouse.addListener('mouseenter', () => console.log('mouseenter', mouse.position));
mouse.addListener('mousemove', () => console.log('mousemove A', mouse.position));
mouse.addListener('mousemove', () => console.log('mousemove B', mouse.position));
Not mouse position, but, if you're looking for current cursor postion (for use cases like getting last typed character etc) then, below snippet works fine.
This will give you the cursor index related to text content.
window.getSelection().getRangeAt(0).startOffset
I envision that maybe you have a parent page with a timer and after a certain amount of time or a task is completed, you forward the user to a new page. Now you want the cursor position, and because they are waiting, they aren't necessarily touching the mouse. So track the mouse on the parent page using standard events and pass the last value to the new page in a get or a post variable.
You can use JHarding's code on your parent page so that the latest position is always available in a global variable:
var cursorX;
var cursorY;
document.onmousemove = function(e){
cursorX = e.pageX;
cursorY = e.pageY;
}
This won't help users that navigate to this page by means other than your parent page.
I think i may have a reasonable solution with out counting divs and pixels..lol
Simply use animation frame or a time interval of a function. you will still need a mouse event one time though just to initiate, but technically you position this where ever you like.
Essentially we are tracking a dummy div at all times with out mouse movement.
// create a div(#mydiv) 1px by 1px set opacity to 0 & position:absolute;
Below is the logic..
var x,y;
$('body').mousemove(function( e ) {
var x = e.clientX - (window.innerWidth / 2);
var y = e.clientY - (window.innerHeight / 2);
}
function looping (){
/* track my div position 60 x 60 seconds!
with out the mouse after initiation you can still track the dummy div.x & y
mouse doesn't need to move.*/
$('#mydiv').x = x; // css transform x and y to follow
$('#mydiv)'.y = y;
console.log(#mydiv.x etc)
requestAnimationFrame( looping , frame speed here);
}