Using the onmousedown event handler

JavaScript FAQ | Images FAQ | Keyboard & Mouse Events FAQ  

Question: How do I change an image when the user clicks on it?

Answer: This is very similar to onMouseOver effects. However, the techniques described on this page will work only in Netscape 4.x or Internet Explorer 4.x (or newer browsers) because versions 3.x of both browsers do not support the onMouseDown and onMouseUp event handlers.

Here is a simple example: This image changes when you press the mouse button!
Press the mouse button while pointing at this folder, and it will open. Release the mouse button, and the folder will close.

The <IMG> tag in this example is embedded in a hyperlink that has three event handlers: onMouseDown, onMouseUp and onMouseOut.

<a href="#any_URL"
onMouseDown="handlePress();return true;" 
onMouseUp="handleRelease();return true;" 
onMouseOut="handleRelease();return true;" 
onClick="return false;"
><img name=imgName width=17 height=15 border=0 
alt="This image changes when you press the mouse button!"
In the <HEAD> section of the page, we have JavaScript code that preloads the image files and defines the event handler functions:
<script language="JavaScript">
if (document.images) {
 img_on =new Image();  img_on.src ="../hi-icons/1.gif"; 
 img_off=new Image();  img_off.src="../hi-icons/2.gif"; 

function handlePress() { 
 if (document.images) document.imgName.src=img_on.src;

function handleRelease() {
 if (document.images) document.imgName.src=img_off.src;


Here is a more complex example with several images: This image changes when you point at it!
The code is very similar to the above, except that now the event handler functions take the image's number as a parameter. (To see the actual code, view the source of this page.)


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