// JavaScript Document

	var flag=true;
	function checkinput()
	{
		if(document.getElementById("username").value == "")
					{alert("请输入用户名！");document.getElementById("username").value="";document.getElementById("username").focus();flag=false;return flag;}else{flag=true;}
 
		if(document.getElementById("userpassword").value=="")
			{alert("请输入密码！");document.getElementById("userpassword").value="";document.getElementById("userpassword").focus();flag=false;return flag;}else{flag=true;}
		
      

		
		
		if (flag==true) {flag=checkchar(document.getElementById("username").value)} 
		if (flag==true) {flag=checkchar(document.getElementById("userpassword").value)} 
		
		
		return flag;
	}