function validate(string,format)
  {
 switch(format)
    {
	       case "null":
				{
				
				if(string.search(/\S/)==-1)
				     return false;
				else
				    return true;
				}
	         break;
	     case "email":
	          {
	         if (string.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/) != -1)
			      return true;
			      else
			     return false;
			  
	         }
	       break;

	     case"numeric":
	       {
	          reZip= new RegExp(/(^\d{6}$)|(^\d{5}-\d{4}$)/);
              if (!reZip.test(string))
	             {
                     return false;
	             }
	           else
	            {
	            return true;
	            }
            }
		  break;
    default: alert(format);
     }
}