Salesforce VisualForce 使用apex:actionFunction调用后台方法

<apex:inputHidden id="flag" value="{!flag}"/>
<apex:actionFunction action="{!searchCon}" name="searchCon1" oncomplete="return savemessage()" reRender="form1">
<apex:param name="uname" assignto="{!username}" value=""/>
<apex:param name="pword" assignto="{!password}" value=""/>
</apex:actionFunction>
function savemessage()
{
if(document.getElementById("page:form1:flag").value == "false"){
alert("用户名密码错误！");
return false;
}
else
{
window.location.href="/apex/UserInformationPage";
}
}
function save()
{
searchCon1(document.getElementById('Username_pop').value,document.getElementById('Password_pop').value);
}

后台类
global class GYZ_UserLoginController
{
public ContractNew__c[] clist{get;set;}
public Boolean flag{get;set;}
public String username{get;set;}
public String password{get;set;}
global GYZ_UserLoginController()
{
clist = new ContractNew__c[]{};
}
global void searchCon()
{
clist = [Select id From ContractNew__c Where GYZ_UserName__c =:username and GYZ_Password__c =: password];
System.debug();
if(clist.size() > 0)
{
flag = true;
}
else
{
flag = false;
}
}
}