Width of an inline element - javascript

How do know width of an inline element, without adding to document?
With adding
var span = document.createElement('span');
span.innerHTML = 'Hello, world!';
span.offsetWidth; //0
document.body.appendChild(span);
span.offsetWidth; //70
How without adding to document?
Sorry for my english)

The width of an element does obviously depend on the styles used (e.g. on the font size), so it is impossible to compute the width of the element without knowing where it is in the DOM.
You may add it to some invisible element if you don't want it to show on the screen.

You cannot get a width of an element if the element itself is not part of the DOM.
You need to append it, but you may also position it outside the visible area (with position: absolute and a negative left/top property) and remove it once you got the width

Until the element is added, there's no way to know for sure how wide it is, because it depends on the styling context.
jQuery's width() method has a trick that it uses for display: none elements, I don't know if it will work for an element that hasn't even been added to the DOM (it works by temporarily showing the element, getting the width, then hiding it again).

Related

How to know if my element is overflowed

I have a slider that contains N elements. Each element will by translated by N pixels when the user click on the next button. When the element is out of the wrapper div, it disappears because it is overflowed by another element.
My plugin does not use any margins, just the transform property.
I would like to know if there is a way to know if my element is out of the div. :visible does not work for my problem because the element is already visible but overflowed.
If I understand correctly, one way to do it would be to compare the position of this element to the size (width/height or both) of his parent.
With Jquery you could do it this way:
<script>
//This is the position of the right side of the element
//relative to his parent
var rightPos = $("#element").position().left + $("#element").width();
//And bottom side
var botPos = $("#element").position().top + $("#element").height();
if (rightPos > $("#element").parent().width()) {
//The element is outside the right limit of the the parent block
} else if (botPos > $("#element").parent.height()) {
//It's outside the bottom limit of the parent block
}
</script>
If it's not the parent you could then adapt this code to compare the position to the width of the correct div, preferably by using the jquery offset() method instead of position().
By determine parent width and get child width then use if condition
if($('span').width() > divWidth){
alert('Overflowed!');
// do something!
}
jsFiddle Demo
if you update your question with your html then I can update with your codes.
You could give the wrapper div the CSS property of overflow: hidden
This would mean that any elements inside of it are not visible when they leave the bounds of the wrapper.
Otherwise you could check whether your element is outside of the wrapper div using jQuery to compare the position to that of the parent.
There is a nice tool for testing if an element is visible on the screen.
Detect if a DOM Element is Truly Visible
It looks at an object and checks each of its parents to see if it’s still visible to the user.

Changing div text layouts the whole document

I want to change the text inside a div with javascript (jQuery is ok too).
There are a few to do that:
element.innerText
element.innerHTML
element.textContent
$(element).text()
$(element).html()
But when I use the above methods, the whole document is affected and not only the div.
See chrome timeline below which refers to this fiddle
Is there a way to update the text inside the div without affecting the whole document?
Because updating the text affects the width/height of the element and the flow of the page, the entire document usually has to be laid out again whenever the DOM changes. However, you can do stuff so only part of the document needs to be re-laid out.
From http://wilsonpage.co.uk/introducing-layout-boundaries/
To be a layout boundary, the element must:
Be an SVG root (<svg>).
Be a text or search <input> field.
or:
Not be display inline or inline-block
Not have a percentage height value.
Not have an implicit or auto height value.
Not have an implicit or auto width value.
Have an explicit overflow value (scroll, auto or hidden).
Not be a descendant of a table element.
If you make the element you're updating a layout boundry, only the part of the document inside your element needs to be updated. However, keep in mind were talking about optimizations of less than a millisecond, and pre-mature optimizations are generally considered bad practice.
Note: Do not start an id attribute with a number. It may cause problems in some browsers.
http://www.w3schools.com/jquery/sel_id.asp

Saving off an element's CSS and reapply later

Is it possible to save off all CSS that is 'currently' applied to an element, then later reapply it? I am working on a sticking table header, and when I i change position:fixed it loses all the applied styles. I currently save off the column widths and reapply to the table header with:
$('#tableHeader').css({
position:'fixed',
width:$('#tablePanel').width(),
top:$('#top').height(),
});
$('.column1Value').width(col1Width);
$('#col1').width(col1Width);
$('.column2Value').width(col2Width);
$('#col2').width(col2Width);
$('.column3Value').width(col3Width);
$('#col3').width(col3Width);
$('.column4Value').width(col4Width);
$('#col4').width(col4Width);
$('.column5Value').width(col5Width);
$('#col5').width(col5Width);
$('.column6Value').width(col6Width);
$('#col6').width(col6Width);
$('.column7Value').width(col7Width);
$('#col7').width(col7Width);
This make the columns the correct size and line up closely, but there is extra padding or margin being applied from somewhere I can't completely figure out (bootstrap probably), and this makes the headers and columns not line up. I was hoping for something like:
var savedCSS = $('#table').css(); and retrieve it like $('#table').css(savedCSS)
You could save off the individual styles that you are interested in one by one and then re-apply them later using the jQuery("selector").css("styleName") method that you alluded to, but I don't think there's an easy way to do them all at once. It's not impossible, but wouldn't be very efficient and probably wouldn't actually give you the result you want, once the element is in its new position.
After the discussion, we found that the sizing issue wasn't really due to the styles, but due to the element that the width was being calculated from.
When the element is positioned normally in the page-flow, it uses its most recent positioned parent's width and then takes off margin to find the width of the child content.
When the element is removed from the page flow, its width is then independent of the parent. So to get the two to match up, record the parent's width rather than the element itself and set the width to match the parent, instead of trying to maintain the element's width.

How to make an element's height increase with every child added to it

I have a <div> that has children appended to it by a script. These children elements are automatically appended by a PHP script and positioned using position:absolute. I tried to give the parent <div> the style min-height:400px allowing the elements appended to the <div> to increase the parent's height. The only problem is that the height does not increase when I do this. Does anybody know what I can do to fix this?
EDIT: I am not able to use position:relative for positioning my elements. Are there any solutions that allow for position:absolute.
Yes you can use position absolute (yeee♥!)
LIVE DEMO TEST CASE
By simply doing:
$(this).height( this.scrollHeight );
or with pure JS:
this.style.height = this.scrollHeight ;
and adding this to your element's CSS:
overflow:hidden;
overflow-y:auto;
Edit:
The demo tested fine in IE10, Firefox, Chrome, Safari, and Opera.
The key point here is setting the overflow value for the x or y axis (whichever dimensions you need the size of) to auto, rather than the default value of visible. Then the scrollWidth or scrollHeight property can be used on the HTML DOM object to get the full size of the element, including any absolutely-positioned descendants.
Odd as it seems, this is entirely consistent with the fact that setting overflow:hidden for a container clips any absolutely-positioned descendants. Apparently, elements with position:absolute aren't quite as "out of the flow" as we've always been told :)
You should not use position: absolute for this because stuff that is positioned that way will be pulled out of the normal render flow. This results in the parent not noticing that its content s acually very high. Use position: relative for the child div's. This way the parent will grow automatically.

Get height of div dependent on text inside

I have a DIV with some text inside. But the height of the DIV starts at 0px, it also has an 'overflow:hidden'. After that i'm using an animation system to increase the height of the DIV. But i can't give the DIV a fixed height because the length of the text inside the DIV varies.
Is there a way to tell what the height of the DIV will be when its big enough to fit all content inside it?
I have done a horrible hack but see if this is good enough.
Basically you get the content height by setting the height to auto, then resetting it to zero and finally using your animation function, like this :
var tempHeight = $(".sample").css({"height" : "auto"}).height();
$(".sample").css({"height" : "0px"}).animate({
height : tempHeight
},1000);
Where .sample is the reference to the div with the variable text content. Check out the demo for a better understanding.
Pure Javascript Version :
document.getElementById("sample").style.height = "auto"; //The id of this div is 'sample'
var tempheight = document.getElementById("sample").offsetHeight;
document.getElementById("sample").style.height = "0px";
/*
Custom Animation function, Use tempheight to get the full content
*/
DEMO For The Jquery Version
Maybe you can try this:
Put the text inside another DIV like...
<div>
<div>some text</div>
</div>
Then animate the outer div (which as an hidden overflow) according to the height of the inner div (which has not an hidden overflow).
Hope this helps
Depending on what you're doing/using you don't need to know the height because setting it to "auto" will ensure it expands to fill the content.
However, you could also not set the heights to 0 until you know the height by using javascript to get it. For example in jQuery:
$("div").each(function()
{
$(this).attr("data-height", $(this).height()).css({"height": "0", "overflow": "hidden");
});
Now each div has an attribute called "data-height" that has the value of it's original height. You can then use this to expand the div when you need to.
Just before animating the showing of the div, clone the div and get rid of the height:0px constraint (change the height to auto, for example). Then grab the height of that cloned div for use in your animation.
In jQuery, this would look something like:
var myDiv = $('div');
var myDivClone = div.clone().insertAfter(myDiv).css('height','auto');
var myDivHeight = myDivClone.outerHeight();
myDivClone.remove();
myDiv.animate({height: myDivHeight}, 250);
Note the importance of actually cloning the element in question as opposed to just creating a new one and filling it with the same contents. You need to recreate the element exactly (other than the height modification you do afterwards), including classes, etc.
ALSO note the importance of injecting it into the DOM immediately after myDiv. This is so that the same CSS will affect it as affects myDiv at time of height calculation. The only potential exception to this is if you're using a :last-child selector in your CSS, and the clone ends up becoming the last child of the parent element. But that kind of issue should be easy enough to get around.
how about dropping the text in a off screen div first and getting the dimensions from that?
if(el.scrollHeight > el.offsetHeight || el.scrollWidth > el.offsetWidth)
{
//keep making element bigger
el.style.height = parseInt(el.style.height) + 2 + "px"
}
You could stick this snippet inside some sort of recursive function or while loop. Essentially you are checking to see if there is more content outside of the viewable area that a scroll-bar would show.

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