function getLen(objtxt,objout,maxlength)
		{
		    var num=parseInt(objtxt.value.length);
		    if(maxlength!=-1)
		    {
		        num=maxlength-num;
		    }
		    if(num<0)
		    {
		        num=0;
		    }   
			
			objout.innerHTML=num;
		}
		function SetHome(obj, vrl) {
                    try {
                        obj.style.behavior = 'url(#default#homepage)';
                        obj.setHomePage(vrl);
                    } catch(e) {
                        if (window.netscape) {
                            try {
                                netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
                            } catch(e) {
                                alert("抱歉！您的浏览器不支持直接设为首页。请在浏览器地址栏输入“about:config”并回车然后将[signed.applets.codebase_principal_support]设置为“true”，点击“加入收藏”后忽略安全提示，即可设置成功。");
                            }
                            var prefs = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch);
                            prefs.setCharPref('browser.startup.homepage', vrl);
                        }
                    }
                }
                
                function setTxt() {
                    var t = document.getElementById("tbUrl");
                    t.select();
                    window.clipboardData.setData('text', t.createTextRange().text);
                    alert('地址已复制到剪切板')
                }