function checkform(form)
{	 											
			if(isNull(form.client_name.value))
				{
					alert("Please enter your  username.");
					form.client_name.focus();
					return false;
				}									
			if(isNull(form.client_p.value))
				{
					alert("Please enter your  password");
					form.client_p.focus();
					return false;
				}													
	return true;
}						
					
function isNull(aStr)
	{
		var index;		
		for (index=0; index < aStr.length; index++)
			if (aStr.charAt(index) != ' ')
				return false;		
		return true;
}