Making a page as default homepage in a browser could be performed by javascript in some browsers. But most of modern browsers have this feature disabled by default, because of security reason. Here is the code that should work for IE and FireFox:
<script type="text/javascript">
function makeHomepage(){
if(document.all){
document.body.style.behavior='url(#default#homepage)';
document.body.setHomePage(location.href);
}
else if(window.sidebar){
if(window.netscape){
try{
netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
}
catch(e){
alert("This action is not available in your browser.");
}
}
var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components. interfaces.nsIPrefBranch);
prefs.setCharPref('browser.startup.homepage',location.href);
}
return false;
}
</script>
Place the code above within tags of your page, then use this link on the same page in the body of page:
<a href="javascript:;" onclick="makeHomepage();">Make homepage</a>