Hi. I am just learning javascript ,I am having trouble for swapping Images by using mouseover function , I have more than 50 images, and they should be thumbnails, and when i use mouseover, the Image should display in a preview window, please help me

What do you mean when you say preview window?

When you do onmouseover, you can take the src of that image and set it to some other image:

<img src="...." onmouseover="document.getElementById('[B]target[/B]').src = this.src" 
onmouseout="" />

<img src="" id="[B]target[/B]" />

For a complete reference:
http://www.w3schools.com/jsref/dom_obj_image.asp

The above link has the properties of the image object which you get when you do:
document.getElementById('target')

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.