function checkform(){
	var theForm = document.forms['loginform'];
	if (!theForm) {
		theForm = document.loginform;
	}
	if(theForm.username.value==""){
		alert("登录帐号不能为空！");
		theForm.username.focus();
		return false;
	}
	if(theForm.password.value==""){
		alert("登录密码不能为空！");
		theForm.password.focus();
		return false;
	}
}
function ReCode(){
    var theForm = document.forms['loginform'];
    if (!theForm) {
	theForm = document.loginform;
    }
    theForm.imagecode.src = "/site/img?"+ Math.random();
}
function Submit() {
    var theForm = document.forms['loginform'];
    if (!theForm) {
	    theForm = document.loginform;
    }
    theForm.submit();
}