window.onerror = function(sMessage, sUrl, sLine) {
//return true;
}
function $F(id) 
{
return document.getElementById(id).value;
}

function $(id) 
{
return document.getElementById(id);
}

  function  input_onkeypress(event)  
   {   
  if(event.keyCode==13){   
  login();  
  }   
  } 

function chklogin()
{
L_username=$F("username");
L_password=$F("password");
if(L_username=="")
{
alert("Please input your username.")
$("username").focus();
return;
}
if(L_password=="")
{
alert("Please input your password.")
$("password").focus();
return;
}
document.form1.submit();
}