/* ======================================================================
FUNCTION:  	IsInt
====================================================================== */
function IsInt(teststring) 
{
	// Return immediately if an invalid value was passed in
	if (teststring+"" == "undefined" || teststring+"" == "null" || teststring+"" == "")	
		return false;

	var isValid = true;

	// convert to a string for performing string comparisons.
	teststring += "";	

	for (i = 0; i < teststring.length; i++) 
       {
    	   if (!((teststring.charAt(i) >= "0") && (teststring.charAt(i) <= "9"))) 
            {
             	isValid = false;
       	      break;
		       }      
        } // END for   
   
  return isValid;
}  // end IsInt