I cannot seem to get this script to work. Can anyone please help? The DIV's width is not defined. It just stretches across the whole page.
<html>
<head>
<style type="text/css">
#box{
height:100px;
border:3px;
border-style:solid;
border-color:#000;
}
</style>
<script>
document.getElementById('box').style.width="10px";
</script>
</head>
<body>
<div id="box"></div>
Your script is running before the <div> is rendered on the page. Try it like this:
<html>
<head>
<style type="text/css">
#box{
height:100px;
border:3px;
border-style:solid;
border-color:#000;
}
</style>
</head>
<body>
<div id="box"></div>
<script type="text/javascript">
document.getElementById('box').style.width="10px";
</script>
</body>
</html>
And don't forget to close your <body> and <html> tags.
To prove that it is, look at this example. I moved the script back to the <head> section and changed the width setting to run when the window is finished loading.
<html>
<head>
<style type="text/css">
#box{
height:100px;
border:3px;
border-style:solid;
border-color:#000;
}
</style>
<script type="text/javascript">
alert('test');
window.onload = function() {
document.getElementById('box').style.width="10px";
}
</script>
</head>
<body>
<div id="box"></div>
</body>
</html>
You'll see the 'test' alert message before the box is rendered.
The element does not exist on the page yet. JavaScript can not access/manipulate an element until it has been loaded in the DOM. You can overcome this by moving you <script> block to above the closing </body>. Or use an window.load event.
An example of the former using your code is here - http://jsfiddle.net/ycWxH/
just a reminder, window.onload is fired when page fully loaded.
refer to http://www.javascriptkit.com/dhtmltutors/domready.shtml
<script>
function doMyStuff() = {};
if ( document.addEventListener ) {
document.addEventListener( "DOMContentLoaded", doMyStuff, false );
} else if ( document ) {
document.attachEvent("onreadystatechange",function(){
if ( document.readyState === "complete" ) {doMyStuff();}
});}
</script>