//添加到收藏夹
function AddToFavorite()
{
    if (document.all){
       window.external.addFavorite(document.URL,document.title);
    }else if (window.sidebar){
       window.sidebar.addPanel(document.title, document.URL, "");
    }
}

//设为首页
function setHomepage(){
	if (document.all){
    document.body.style.behavior='url(#default#homepage)';
    document.body.setHomePage(document.URL);
  }else if (window.sidebar){
		if(window.netscape){
       try{ 
          netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect"); 
       }catch (e){ 
 					alert( "该操作被浏览器拒绝，如果想启用该功能，请在地址栏内输入 about:config,然后将项 signed.applets.codebase_principal_support 值该为true" ); 
       }
		} 
    var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components. interfaces.nsIPrefBranch);
    prefs.setCharPref('browser.startup.homepage',document.URL);
	}
}

<a href="#" onclick="setHomepage();">设为首页</a>
<a href="javascript:AddToFavorite();" >添加收藏</a>