ValidatorUpdateIsValid = function() {
    Page_IsValid = AllValidatorsValid(Page_Validators);
    ClearValidatorCallouts();
    SetValidatorCallouts();
} 

 SetValidatorCallouts = function() {
     var i;
     var pageValid = true;
     for (i = 0; i < Page_Validators.length; i++) {
         var inputControl = document.getElementById(Page_Validators[i].controltovalidate);
         if (!Page_Validators[i].isvalid) {
             if (pageValid)
                 inputControl.focus();
             WebForm_AppendToClassName(inputControl, 'error');
             pageValid = false;
         }
     }

     return pageValid;
 }

 ClearValidatorCallouts = function() {
     var i;
     var invalidConrols = [];
     for (i = 0; i < Page_Validators.length; i++) {
         var inputControl = document.getElementById(Page_Validators[i].controltovalidate);
         WebForm_RemoveClassName(inputControl, 'error');
     }
 }

 function WebForm_RemoveClassName(element, className) {
     if (element != null) {
         var current = element.className;
         if (current) {
             if (current.substring(current.length - className.length - 1, current.length) == ' ' + className) {
                 element.className = current.substring(0, current.length - className.length - 1);
                 return;
             }

             if (current == className) {
                 element.className = "";
                 return;
             }

             var index = current.indexOf(' ' + className + ' ');
             if (index != -1) {
                 /* BUG 1: index + 1 instead of index to include one space */
                 element.className = current.substring(0, index + 1) + current.substring(index + className.length + 2, current.length);
                 return;
             }

             /* BUG 2: className.length + 1 instead of className.length in order that the comparison is true */
             if (current.substring(0, className.length + 1) == className + ' ')
                 element.className = current.substring(className.length + 1, current.length);
         }
     }
}

 function WebForm_AppendToClassName(element, className) {
     var current = element.className;
     if (current) {
         if (current.charAt(current.length - 1) != ' ') {
             current += ' ';
         }
         current += className;
     }
     else {
         current = className;
     }
     element.className = current;
 }