function onlyShow(divId)
{
	document.getElementById(divId).style.display="";
}
function onlyHide(divId)
{
	document.getElementById(divId).style.display="none";
}

function validateLogin()
{ 
	err = 0;
	$('#username-err').html('');
	$('#password-err').html('');

	username = $.trim(document.login_form.username.value);
	password = $.trim(document.login_form.password.value);
	
	strRegExp = "[^A-Za-z0-9\\s]";
	
	charpos = username.search(strRegExp);
	if(username.length <= 0)
	{ 
		$('#username-err').html('Please enter username.');
		err=1;
		
	}
	else
	{
		if (charpos >=0)
		{
			$('#username-err').html('Username should be alpha-numeric.');
			err=1;
		}
	}

	if(password.length <= 0)
	{ 
		$('#password-err').html('Please enter password.');
		err=1;
		
	}
	

	if(err == 1)
	{ 
		return false;
	}
}