<html>
<head>
<script type="text/javascript">
// Wait for the page to load first
window.onload = function() {
//Get a reference to the link on the page
// with an id of "mylink"
var a = document.getElementById("mylink");
//Set code to run when the link is clicked
// by assigning a function to "onclick"
a.onclick = function() {
// Your code here...
//If you don't want the link to actually
// redirect the browser to another page,
// "google.com" in our example here, then
// return false at the end of this block.
// Note that this also prevents event bubbling,
// which is probably what we want here, but won't
// always be the case.
return false;
}
}
</script>
</head>
<body>
<a id="mylink" href="http://www.google.com">linky</a>
</body>
</html>
window.onload = function(){
document.getElementById("DaLink").onclick = function(){
if(funcitonToCall()){
// most important step in this whole process
return false;
}
}
}
if the javascript runs successfully, maybe loading the content in the current page with javascript, the return false cancels the link firing. in other words putting return false has the effect of disabling the link if the javascript ran successfully. While allowing it to run if the javascript does not, making a nice backup so your content gets displayed either way, for search engines and if your code breaks, or is viewed on an non-javascript system.
best book on the subject is "Dom Scription" by Jeremy Keith