Javascript Manipulate Class Names (See related posts)

// ----------------------------------------------------------------------------
// HasClassName
//
// Description : returns boolean indicating whether the object has the class name
//    built with the understanding that there may be multiple classes
//
// Arguments:
//    objElement              - element to manipulate
//    strClass                - class name to add
//
function HasClassName(objElement, strClass)
   {

   // if there is a class
   if ( objElement.className )
      {

      // the classes are just a space separated list, so first get the list
      var arrList = objElement.className.split(' ');

      // get uppercase class for comparison purposes
      var strClassUpper = strClass.toUpperCase();

      // find all instances and remove them
      for ( var i = 0; i < arrList.length; i++ )
         {

         // if class found
         if ( arrList[i].toUpperCase() == strClassUpper )
            {

            // we found it
            return true;

            }

         }

      }

   // if we got here then the class name is not there
   return false;

   }
// 
// HasClassName
// ----------------------------------------------------------------------------


// ----------------------------------------------------------------------------
// AddClassName
//
// Description : adds a class to the class attribute of a DOM element
//    built with the understanding that there may be multiple classes
//
// Arguments:
//    objElement              - element to manipulate
//    strClass                - class name to add
//
function AddClassName(objElement, strClass, blnMayAlreadyExist)
   {

   // if there is a class
   if ( objElement.className )
      {

      // the classes are just a space separated list, so first get the list
      var arrList = objElement.className.split(' ');

      // if the new class name may already exist in list
      if ( blnMayAlreadyExist )
         {

         // get uppercase class for comparison purposes
         var strClassUpper = strClass.toUpperCase();

         // find all instances and remove them
         for ( var i = 0; i < arrList.length; i++ )
            {

            // if class found
            if ( arrList[i].toUpperCase() == strClassUpper )
               {

               // remove array item
               arrList.splice(i, 1);

               // decrement loop counter as we have adjusted the array's contents
               i--;

               }

            }

         }

      // add the new class to end of list
      arrList[arrList.length] = strClass;

      // add the new class to beginning of list
      //arrList.splice(0, 0, strClass);
      
      // assign modified class name attribute
      objElement.className = arrList.join(' ');

      }
   // if there was no class
   else
      {

      // assign modified class name attribute      
      objElement.className = strClass;
   
      }

   }
// 
// AddClassName
// ----------------------------------------------------------------------------


// ----------------------------------------------------------------------------
// RemoveClassName
//
// Description : removes a class from the class attribute of a DOM element
//    built with the understanding that there may be multiple classes
//
// Arguments:
//    objElement              - element to manipulate
//    strClass                - class name to remove
//
function RemoveClassName(objElement, strClass)
   {

   // if there is a class
   if ( objElement.className )
      {

      // the classes are just a space separated list, so first get the list
      var arrList = objElement.className.split(' ');

      // get uppercase class for comparison purposes
      var strClassUpper = strClass.toUpperCase();

      // find all instances and remove them
      for ( var i = 0; i < arrList.length; i++ )
         {

         // if class found
         if ( arrList[i].toUpperCase() == strClassUpper )
            {

            // remove array item
            arrList.splice(i, 1);

            // decrement loop counter as we have adjusted the array's contents
            i--;

            }

         }

      // assign modified class name attribute
      objElement.className = arrList.join(' ');

      }
   // if there was no class
   // there is nothing to remove

   }
// 
// RemoveClassName
// ----------------------------------------------------------------------------