function loginCheck(){
	//验证昵称
	if(document.getElementById("userNick").value == ""){
		alert("Please input username！\n请输入用户名！");
		document.getElementById("userNick").focus();
		return false;
	}
	
	//验证密码
	if(document.getElementById("userPassword").value == ""){
		alert("Please input password！\n请输入密码！");
		document.getElementById("userPassword").focus();
		return false;
	}
	
	//验证验证码
	if(document.getElementById("validateCode").value == ""){
		alert("Please input verification！\n请输入验证码！");
		document.getElementById("validateCode").focus();
		return false;
	}
}