function check(username,password){
	if(username=="" && password=="")
		{
			window.alert("Please enter your Username & Password");
		}
	else if(username=="")
		{
			window.alert("Please enter your Username");
		}
	else if(password=="")
		{
			window.alert("Please enter your Password");
		}

	else{
		Ext.Ajax.request({
			   url: 'database.php',
			   params: { uname: username},
			   success: function(response, opts){
				   var o= Ext.decode(response.responseText);
			   }
			});
		}
	}