var IsFormValid = false;

function ValidateControl(objName, fieldName, fldType, canEmpty)
{
   var isEmpty = false;
   var isValid = true;
   var validMessage;
   var filter;
   if (IsFormValid == false) return;
   var obj = document.getElementsByName(objName)[0];
   if (obj != null)
   {
      if (fldType == '3')      
          isEmpty = (obj.value == '');
      else if (fldType == '4')  
      { 
      		if (obj.value != undefined)
      		{
      			isEmpty = (obj.value == '');
      		}
      		else
      		{
          		isEmpty = (obj.innerText == '');
          	}
      } else if (fldType == '5')
      {          
          isEmpty = (obj.value == '');
          if (!(isEmpty == true && canEmpty == true))
          {
              filter = /^.+@.+\..{2,3}$/
          	  isValid = filter.test(obj.value);
              if (!isValid) validMessage = 'Please enter a valid email such as \'john.doe@acme.com\'.';
          }          
      } 
      else if (fldType == '6')
      {
          isEmpty = (obj.value == '');
          if (!(isEmpty == true && canEmpty == true))
          {
              filter = /^\d+$/
         	  isValid = filter.test(obj.value);
              if (!isValid) validMessage = 'Please enter a valid number.';
          } 
      }     

      if (canEmpty == false && isEmpty == true)
      { 
         alert(fieldName + ' is required.');
         obj.focus();         
         IsFormValid = false;
      } else if (isValid == false)
      {
         alert(validMessage);
         obj.focus();         
         IsFormValid = false
      }
   }
   else
     alert(objName + ' not found.');
}