How to add a div into html code using Javascript - javascript

I am trying to create a function that is supposed to take the mouse coordinates and draw a small radius using their values and inserting them into CSS left and top positions. I am stuck at the part where I am supposed to add the div that I have created to the html. Please forgive me if I am not being clear enough.
<script type="text/javascript">
function getcoord(event) {
var x=event.clientX ;
var y=event.clientY ;
follow(x,y);
function follow(xcor,ycor) {
folowHTML =
'<div style="'background-color:red;width:30px;height:30px;'
+'border-radius:30px;position:absolute;left:''+xcor;'top:'+ycor';">'
+'</div>';
};}
</script>
<body onmouseover="getcoord(event);">
</body>

Maybe try add this line:
document.body.innerHtml = folowHTML + document.body.innerHtml;
Also You should probably change position absolute to fixed I think.
Edit: This was bad way
Here You have answer:
Instert element before </body> tag with vanilla JavaScript

You could try something like this...
<style>
#follow {
background-color: #fff;
border:1px solid red;
border-radius: 50%;
height: 20px;
margin:-10px 0 0 -10px;
position: absolute;
width: 20px;
z-index: 10;
}
</style>
<script>
function initFollow(){
var follow = document.createElement('div');
follow.setAttribute('id','follow');
document.getElementsByTagName("body")[0].appendChild(follow);
window.addEventListener('mousemove', function(e) {
var left = e.pageX + 'px',
top = e.pageY + 'px';
follow.style.left = left;
follow.style.top = top;
}, false);
}
window.addEventListener('load',initFollow,false);
</script>

Related

How to let the coodinates of the cursor follow the cursor when hovering over a rectangle?

The following code always shows the coordinates of the cursor below the cursor:
function showCoords(e) {
var x = event.clientX;
var y = event.clientY;
var coor = "(" + x + ", " + y + ")";
document.getElementById("box").innerHTML = coor;
var bx = document.getElementById("box");
bx.style.left = e.pageX - 50;
bx.style.top = e.pageY + 20;
}
function clearCoords() {
document.getElementById("box").innerHTML = "";
}
div.relative {
position: relative;
width: 400px;
height: 300px;
border: 1px solid black;
}
div.abs {
position: absolute;
top: 100px;
right: 50px;
width: 200px;
height: 100px;
background-color: yellow;
}
<body onmousemove="showCoords(event)">
<div class="relative">
<div class="abs" onmousemove="showCoords(event)" onmouseout="clearCoords()"></div>
</div>
<div id="box" style="width:100px; height:30px; position:absolute"></div>
</body>
I only want the coordinates to be visible when the mouse pointer is hovering over the yellow rectangle.
If I change <body onmousemove="showCoords(event)"> to <body>, the coordinates are never visible.
How do I get the coordinates be visible only when hovering over the yellow rectangle?
Move the onmousemove listener from the body to the element you want to listen on - div.abs in this case.
I'd recommend not using the onmousemove attribute, in favour of using an entirely javascript solution - just to keep javascript-y things together. Something like (untested)
var listenOn = document.querySelector(".abs");
listenOn.addEventListener("mousemove", ShowCoords);

Update Distance Between Elements

I have two elements, and one is moving towards the other. I am trying to get the new distance as it moves closer. Consider the code below:
<html>
<center>
<body onload = 'start()'>
<div class='field'>
<div id='bull'></div>
<div id='mount'></div>
</div>
<button id='one'>DO</button>
</body>
</center>
<style>
.field{
width: 440px;
height: 260px;
background: rgba(0, 0, 0, .2);
margin-top: 30px;
border: 1px solid #222;
border-radius: 10px;
}
#bull{
width: 15px;
height: 10px;
background: #000;
border-top-right-radius: 5px;
border-bottom-right-radius: 5px;
position: absolute;
}
#mount{
width: 60px;
height: 30px;
background: rgba(20, 10, 45);
color: #fff;
border-radius: 4px;
margin-top: 210px;
}
</style>
<script type='text/javascript'>
function start() {
var ball = document.getElementById('bull');
var button = document.getElementById('one');
var mount = document.getElementById('mount');
button.addEventListener('click', go);
var x_pos = 0;
var y_pos = 0;
var bounce_point = 200;
var ball_dim = ball.getBoundingClientRect();
var ball_h_half = ball_dim.width / 2;
var ball_w_half = ball_dim.height / 2;
var mount_dim = mount.getBoundingClientRect();
var mount_h_half = mount_dim.width / 2;
var mount_w_half = mount_dim.height / 2;
function go() {
for(x_pos = 0; bounce_point > x_pos; x_pos++) {
ball.style.margin = x_pos + "px";
ball.style.transition = x_pos/2 + "s";
var dist = ((ball_h_half - mount_h_half)*(ball_w_half - mount_w_half)) + ((mount_h_half - ball_h_half)*(mount_w_half - ball_w_half));
console.log(dist);
if(dist < 3) {
console.log('One');
}
}
}
}
</script>
When bull reaches comes within 3px of mount, nothing happens... I've pretty much explained the issue as best as I can.
**
When bull reaches comes within 3px of mount, nothing happens... I've pretty much explained the issue as best as I can.**
Well i tried a little bit more, and your logic doens't seem to fit to what you want to do. First of all, you probably noticed your value in the log doesn't change.
It could have been because the values are retreived outside the loop, but not only (they actually have to be in the loop to be updated). You have 2 other problems: first, you are measuring the elements width and height, which don't take account of margin or other positioning. Your elements don't change size, so the value also won't. The other problem is actually the transition itself on the movement. Because of the delay, all your loop iterations are most probably done, and the margin already set to its final value when your "bull" effectively starts to move. It means that in the loop, you can't detect the position change, the element having not started to move yet. Using the value that was just set (margin) instead of detecting the real position of the element should show a progression for the value, but it makes harder to detect the collision because your 2 elements don't have the same positioning rules and you can't just compare the margins.
Here is a quick example that gets updated values (because the transition has been disabled, if you enable back, the problem comes again). You'll notice your calculation for the collision is wrong too. You can't just compare a distance between 2 corners for that, for a rectangle it's rather "has gone beyond left vertical edge AND has gone beyond top horizontal edge" (this of course takes only in account the top left corner, to be complete, it should also be added that it must not have reached the right or bottom edge yet).
Well, I can't propose you an all ready solution, but this addresses your code main issues:
<html>
<center>
<body onload = 'start()'>
<div class='field'>
<div id='bull'></div>
<div id='mount'></div>
</div>
<button id='one'>DO</button>
</body>
</center>
<style>
.field{
width: 440px;
height: 260px;
background: rgba(0, 0, 0, .2);
margin-top: 30px;
border: 1px solid #222;
border-radius: 10px;
}
#bull{
width: 15px;
height: 10px;
background: #000;
border-top-right-radius: 5px;
border-bottom-right-radius: 5px;
position: absolute;
}
#mount{
width: 60px;
height: 30px;
background: rgba(20, 10, 45);
color: #fff;
border-radius: 4px;
margin-top: 210px;
}
</style>
<script type='text/javascript'>
function start() {
var ball = document.getElementById('bull');
var button = document.getElementById('one');
var mount = document.getElementById('mount');
button.addEventListener('click', go);
var x_pos = 0;
var y_pos = 0;
var bounce_point = 200;
var ball_dim, ball_x, ball_y, mount_dim, mount_x, mount_y, diff_x, diff_y;
var stayInLoop = true;
//ball.style.transition = "0.4s"; //i don't know why you updated the transition time based on position, changed to a fixed value outside the loop because it's quicker for the example
function go() {
for(x_pos = 0; bounce_point > x_pos && stayInLoop; x_pos++) {
ball_dim = ball.getBoundingClientRect();
ball_y = ball_dim.top + 10; // +10 because we're considering the bottom edge of bull
ball_x = ball_dim.left + 15; // +15 because we're considering the right edge of bull
mount_dim = mount.getBoundingClientRect();
mount_y = mount_dim.top;
mount_x = mount_dim.left;
diff_x = mount_x - ball_x;
diff_y = mount_y - ball_y;
console.log(diff_x, diff_y);
ball.style.margin = x_pos + "px";
if(diff_x < 3 && diff_y < 3) {
console.log('One');
stayInLoop = false;
}
}
}
}
</script>
EDIT/SUGGESTION: i suggest looking at window.requestAnimationFrame() MDN doc here for a better control on animations

javascript chatbox / messenger script

I'm trying to write a facebook like chatbox, but i've encountered a small problem.
I'm using the following code (it's only test code, so it's not really clean):
css code:
#messenger {
position: fixed;
bottom: 0px;
right: 10px;
width: 200px;
height: 300px;
z-index: 4;
background-color: #ECECEC;
border: 1px solid #000;
}
#messenger.p {
text-align: right;
}
#contacts {
margin: 5px 5px 5px 5px;
}
#chatspace {
position: fixed;
bottom: 0px;
right: 240px;
height: 20px;
left: 20px;
background-color: #ECECEC;
border: 1px solid #000;
z-index: 4;
}
.chatbox {
position: absolute;
bottom: 0px;
width: 200px;
height: 200px;
z-index: 4;
background-color: #ECECEC;
border: 1px solid #000;
}
html/javascript code:
<script type="text/javascript">
var i = 0;
function oc_chatbox() {
if (i == 0) {
document.getElementById('contacts').style.visibility = 'hidden';
document.getElementById('messenger').style.height = '20px';
i = 1;
}
else {
document.getElementById('contacts').style.visibility = 'visible';
document.getElementById('messenger').style.height = '300px';
i = 0;
}
}
function new_chat(userid) {
var new_right;
new_right = document.getElementById('messenger').style.right;
//alert('old value: '+ new_right);
new_right += 20;
//alert('New value of right: '+ new_right);
document.getElementById('chatspace').innerHTML = '<div id="'+userid+'" class="chatbox" style="right: '+new_right+'px;"></div>';
//document.write('<div id="'+userid+'" class="chatbox" style="right: '+new_right+'px;"></div>');
}
</script>
<div id="chatspace"></div>
<div id="messenger">
<p>Collapse</p>
<div id="contacts">
<ul>
<li>contact A</li>
</ul>
</div>
</div>
the problem is, that when I try to add new chats to the chatbar, i can't seem the place them next to each other.
anyone who can help ?
EDIT:
so i changed to javascript code to:
var last = null;
function new_chat(userid) {
if(userid==null)
userid = "user666";
var new_right;
var margin = 10;
var messenger = window.last==null?document.getElementById('messenger'):window.last; //Take the messenger or the last added chat
new_right = document.body.clientWidth-messenger.offsetLeft; //Compute the window size
console.log(new_right); //Log the number
new_right += margin; //keep spaces between divs
var newChat = document.createElement("div"); //DOM create DIV
newChat.id = userid;
newChat.className = "chatbox shadow";
newChat.style.right = new_right+"px";
newChat.innerHTML = '<p>'+userid+'</p><p><textarea></textarea></p>';
window.last = newChat; //Remember whichever is last
document.body.appendChild(newChat);
}
and now it works, thanks !
You cannot get an element right offset using its style, unlest the style is set and valid. Instead you must get element.offsetLeft and size of window area and do this:
new_right = windowSize()[0]-messenger.offsetLeft;
Where window size is this function.
Here is my, working, version of your function:
var last = null;
function new_chat(userid) {
if(userid==null)
userid = "user666";
var new_right;
var margin = 20;
var messenger = window.last==null?document.getElementById('messenger'):window.last; //Take the messenger or the last added chat
new_right = windowSize()[0]-messenger.offsetLeft; //Compute the window size
console.log(new_right); //Log the number
new_right += margin; //keep spaces between divs
var newChat = document.createElement("div"); //DOM create DIV
newChat.id = userid;
newChat.className = "chatbox";
newChat.style.right = new_right+"px";
window.last = newChat; //Remember whichever is last
document.body.appendChild(newChat);
}
You may get errors if console is not defined in your brouwser. But in such case you should take a better browser. Normally, the if(console!=null) is put in code.
And here is the link.
You should try adding a float style.
.chatbox {
float: right;
}
Add that to your chatbox styles. You may need to mess around a bit to make sure the float doesn't mess with your other elements. You may need a better container for them.
If you want to get really fun, you can add .draggable() from jQuery, and you can have them snap to your chat bar. You can then change the order of your chats.

Moving css scaled div using javascript

I have posted my problem at http://jsfiddle.net/ugnf4/ as it would be make it easier.
Below is my html / javascript code
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<div id="mainContainer">
<div id="pageContainer" style="background: #cdcdcd;"></div>
</div>
<style>
BODY {
margin: 0px;
padding: 0px;
}
#pageContainer {
position: relative;
margin: 10px auto;
-webkit-transform-origin:50% 20%;
-webkit-transform:scale(1.37);
width: 1218px;
height: 774px;
border: 1px solid #000000;
}
#mainContainer {
width: 100%;
overflow: hidden;
}
</style>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
</script>
<script type="text/javascript">
$(document).ready(function() {
setHeight();
$(window).resize(setHeight);
});
function setHeight()
{
$('#mainContainer').css({'height': $(window).height()});
}
$('#mainContainer').mousemove(function (e) {
});
</script>
</body>
</html>
Currently #mainContainer div has overflow hidden as i dont want to show scroll bars and #pageContainer div (inner div) is scaled at 1.37 using css3, as in certain cases based on screen / browser width height #pageContainer's content would be hidden because of overflow hidden.
I want to code javascript so that if somebody moves cursor in #mainContainer, based on position of mouse X and Y co-ordinates I would like to move #pageContainer so that similar position of #pageContainer would be visible (I hope it is clear).
I m having problem as I m using -webkit-transform-origin, unable to understand how to move #pageContainer around with respect to mouse co-ordinates of #mainContainer.
UPDATE:
I m looking something like what happens in issuu.com website when you open an ebook and zoom it more than the browser size (Should make it more clear)
I m looking for algo or pointer how to achieve it (how to calculate it) not necessarily a working script.
How can this be achieved.
Below is working html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<div id="mainContainer">
<div id="pageContainer" >
<div id="pageContainerInner"style="background: #cdcdcd;">
</div>
</div>
<style>
BODY {
margin: 0px;
padding: 0px;
}
#pageContainer {
margin: 10px auto;
-webkit-transform-origin:50% 20%;
-webkit-transform:scale(1.37);
width: 1218px;
height: 774px;
}
#mainContainer {
width: 100%;
overflow: hidden;
}
#pageContainerInner {
position: relative;
width: 1218px;
height: 774px;
border: 1px solid #000000;
top: 0;
left: 0;
}
</style>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
</script>
<script type="text/javascript">
var pageWidth = 1220;
var pageHeight = 776;
var scale = 1.37;
var scaledDelta = 5; //Percentage mouse position approximation
$(document).ready(function() {
setHeight();
$(window).resize(setHeight);
});
function setHeight()
{
$('#mainContainer').css({'height': $(window).height()});
}
$('#mainContainer').mousemove(function (e) {
// Calculate the offset of scaled Div
var offsetX = $('#pageContainer').offset().left;
var offsetY = $('#pageContainer').offset().top;
// Calculate div origin with respect to screen
var originX = (-1 * offsetX) / scale;
var originY = (-1 * offsetY) / scale;
var wWdt = $(window).width();
var wHgt = $(window).height();
// Now convert screen positions to percentage
var perX = e.pageX * 100 / wWdt;
var perY = e.pageY * 100 / wHgt;
// Div content which should be visible
var pageX = perX * pageWidth / 100;
var pageY = perY * pageHeight / 100;
// Calculate scaled divs new X, Y offset
var shiftX = (originX - pageX) + (e.pageX / scale);
var shiftY = (originY - pageY) + (e.pageY / scale);
$('#pageContainerInner').css({'left': shiftX+'px', 'top': shiftY+'px'});
});
</script>
</body>
</html>
Hope this will help others.
I have posted a probable solution at http://jsfiddle.net/PYP8c/.
Below are the modified styles for your page.
BODY {
margin: 0px;
padding: 0px;
}
#mainContainer {
width: 100%;
overflow: hidden;
position: relative;
margin: 10px auto;
-webkit-transform-origin:50% 20%;
-webkit-transform:scale(1.37);
width: 1218px;
height: 774px;
border: 1px solid #000000;
}
#pageContainer {
position:absolute;
top:0px;
}
This is the javascript code for the same.
$(document).ready(function() {
//setHeight();
//$(window).resize(setHeight);
});
function setHeight()
{
$('#mainContainer').css({'height': $(window).height()});
}
$('#mainContainer').mousemove(function (e) {
var contentHeight = $("#pageContainer").height();
var minTop = 774 - contentHeight;
if(minTop>0)
minTop = 0;
var currTop = ((e.pageY-10)/774.0)*(minTop);
document.getElementById("pageContainer").style.top = currTop+'px';
});
Its just a demo on how you could get the text to move based on the mouse coordinates.
You could make a lot of changes, like adding a scrollbar that fades which gives the user a feedback about how much content is still available in both the vertical directions.
Also I have used hard coded values for height, but in your final version I would recommend you get the height of the mainContainer division dynamically.

Modifying cursor property for select portion of an element

I have this HTML that renders a simple arrow sign pointing towards the right:
<!DOCTYPE html>
<html>
<head>
<style>
div { width: 0px; height: 0px; border-left: 20px solid black; border-top: 20px solid transparent; border-bottom: 20px solid transparent; border-right: 20px solid transparent; position: absolute; left: 35px; top: 53px; cursor: pointer; }
</style>
<body>
<div></div>
</body>
</html>
If you hover of it, the cursor turns to pointer. But because it is actually a square div, the cursor turns pointer even if you are just outside the arrow within the perimeter of the div.
So I wrote this Javascript addition such that the cursor turns pointer only when the mouse is hovering over that arrow. For this purpose, I figured the coordinates of the three vertices of the triangle from Firebug ((35,53),(55,73),(35,93) clockwise from top). Then I check whether the point in question lies inside the triangle formed by these 3 vertices. This I do by checking whether the point and the opposite vertex for each edge lies on the same side of that edge or not (if they do, the product of the values obtained by substituting the coordinates of that point for x and y in that equation will be positive).
<!DOCTYPE html>
<html>
<head>
<style>
div { width: 0px; height: 0px; border-left: 20px solid black; border-top: 20px solid transparent; border-bottom: 20px solid transparent; border-right: 20px solid transparent; position: absolute; left: 35px; top: 53px; }
.hoverclass { cursor: pointer; }
</style>
<script src="jquery.js">
</script>
<script>
$(document).ready(function(){
$("div").click(function(e) { alert(e.pageX + " " + e.pageY); });
function l1(x,y) { return y - x - 18; }
function l2(x,y) { return x+y-128; }
function l3(x,y) { return x-35; }
$("div").hover(function(e) {
var x = e.pageX;
var y = e.pageY;
if (l1(x,y)*l1(35,93) >= 0 && l1(x,y)*l1(35,93) >= 0 && l1(x,y)*l1(35,93) >= 0 ) {
$(this).addClass('hoverclass');
}
else { $(this).removeClass('hoverclass'); }
},
function() {
$(this).removeClass('hoverclass');
});
});
</script>
<body>
<div></div>
</body>
</html>
However, the results are not predictable. Sometimes the cursor turns pointer within the triangle only, sometimes outside as well (just as before), and sometimes not at all. I suspect that this is probably due to the hover function working overtime, that may be temporarily hanging the script. Is there any other way to achieve this?
This could be done using HTML5 canvas. Basic idea is to check for pixel color on mousemove on canvas element. This way, your element can be of any form as you wish. Of course, you should make some optimization of following code:
SEE WORKING DEMO
function findPos(obj) {
var curleft = 0, curtop = 0;
if (obj.offsetParent) {
do {
curleft += obj.offsetLeft;
curtop += obj.offsetTop;
} while (obj = obj.offsetParent);
return { x: curleft, y: curtop };
}
return undefined;
}
// set up triangle
var example = document.getElementById('example');
var context = example.getContext('2d');
context.fillStyle = '#000';
context.strokeStyle = '#f00';
context.lineWidth = 1;
context.beginPath();
// Start from the top-left point.
context.moveTo(10, 10); // give the (x,y) coordinates
context.lineTo(60, 60);
context.lineTo(10, 120);
context.lineTo(10, 10);
// Done! Now fill the shape, and draw the stroke.
// Note: your shape will not be visible until you call any of the two methods.
context.fill();
context.stroke();
context.closePath();
$('#example').mousemove(function(e) {
var pos = findPos(this);
var x = e.pageX - pos.x;
var y = e.pageY - pos.y;
var coord = "x=" + x + ", y=" + y;
var c = this.getContext('2d');
var p = c.getImageData(x, y, 1, 1).data;
if(p[3]!='0') $(this).css({cursor:'pointer'});
else $(this).css({cursor:'default'});
});
You'd better use CSS instead. With :before and :after pseudo classes you can do magic. Check out this Pure CSS GUI icons by Nicolas Gallagher.
If you use any CSS pre-processor, these icons can be wrapped up as a mixin, this way required properties can be assigned like this:
#icon > .close(16px, #fff, #E83921);
You can make any shape have cursor pointer with CSS only. The idea is to rotate wrapper container which has overflow: hidden (you can have several of them depending on the shape you need). In case of OP problem this code does a trick:
<div class="arrow"><i></i></div>
.arrow {
margin: 100px;
border_: 1px red solid;
width: 40px;
height: 40px;
overflow: hidden;
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
.arrow i {
height: 65px;
width: 65px;
background-color: green;
content: '';
display: block;
cursor: pointer;
margin: -35px 0 0 11px;
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
See this demo: http://cssdesk.com/PaB5n
True that this requires CSS transform support so it's not cross browser.

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