onmouseover and document.getElementById

SRJ92

Hi! This has been bugging me for quite a while now... I have done many google searches but nothing seems to actually help me.... When i run this script i get the following error: "SCRIPT5007: Unable to set value of the property 'onmouseover': object is null or undefined" I don't know how it doesn't work but if i use onmouseover="show()" and obviosuly remake my function heading it works... I can't use the onmouseover="" as apparently its not the best way of doing it... Cna nayone shine some light on where it could be going wrong? Thanks for all your help!

		#gallery
			{
				position:relative;
				display:block;
				width:800px;
				height:500px;
				margin:20px auto;
				text-align:center;
			}
		#image
			{
				display:block;
				width:800px;
				height:500px;
			}
		#imgBar
			{
				position:absolute;
				display:block;
				width:500px;
				height:80px;
				z-index:2;
				top:400px;
				left:145px;
				display:none;
			}		
	
	<script>
		var galleryImg = document.getElementById('image');
		var bar = document.getElementById('imgBar');
		
		galleryImg.onmouseover = function ()
		{
			bar.style.display = "block";
		};
		galleryImg.onmouseout = function ()
		{
			bar.style.display = "none";
		};
	</script>
</head>
<body>


	![](#)
	

	![](img/gallery/thumbnail1.png)
	![](img/gallery/thumbnail1.png)
	![](img/gallery/thumbnail1.png)
	![](img/gallery/thumbnail1.png)
	



</body>

</html>

J4amieC

An HTML page is interpreted top to bottom. When your javascript runs (in the head) the HTML has not yet been parsed, and therefore does not exist. Put everythng into a function

function runMeOnLoad(){
var galleryImg = document.getElementById('image');
var bar = document.getElementById('imgBar');

galleryImg.onmouseover = function ()
{
    bar.style.display = "block";
};
galleryImg.onmouseout = function ()
{
    bar.style.display = "none";
};

}

And execute onload

SRJ92

Brilliant, thank you :)

sachin_jain

Put your script code where the "section" tag ends (before the body tag ends) and it'll work fine.