UTILITIES_VERSION = 0.1;


/**
 * I'm nothing more than a collection of static utility methods for
 * doing various things.
 */
function Utilities() {}



Utilities.isMSIE = (navigator.appName == "Microsoft Internet Explorer");



/**
 * I remove all the children of the specified parent node.
 *
 * @param parent The node whose children should be removed
 */
Utilities.removeChildren = function(parent) {
	if (typeof parent == "string") {
		parent = document.getElementById(parent);
	}
	if (parent == null) {
		return;
	}
	for (var i = parent.childNodes.length - 1; i >= 0; i--) {
		parent.removeChild(parent.childNodes[i]);
	}
}



/**
 * I return an object with an x and y fields, indicating the object's
 * offset from the top left corner of the document.  The 'offsets'
 * argument is optional; if not provided, one will be initialized and
 * used.  It is exposed as a parameter because it can be useful for
 * computing deltas.  The 'object' parameter can be either an actual
 * document element, or the ID of one.
 *
 * @param object The object to compute the offset of.  May be an object
 *		or the ID of one.
 * @param offsets The starting offsets to calculate from.  In almost
 *		all cases, this should be omitted.
 * @return An offsets object with x and y fields, indicating the
 *		computed offsets for the object.  If an offsets object is
 *		passed, that will be the object returned, though the values
 *		will have been changed.
 */
Utilities.getOffsets = function(object, offsets) {
	if (! offsets) {
		offsets = new Object();
		offsets.x = offsets.y = 0;
	}
	if (typeof object == "string")
		object = document.getElementById(object);
	offsets.x += object.offsetLeft;
	offsets.y += object.offsetTop;
	do {
		object = object.offsetParent;
		if (! object)
			break;
		offsets.x += object.offsetLeft;
		offsets.y += object.offsetTop;
	} while(object.tagName.toUpperCase() != "BODY");
	return offsets;
}



/**
 *
 */
Utilities.listAppend = function(list, value, delimiter) {
	if (typeof delimiter == "undefined")
		delimiter = ",";
	if (list == "")
		return value;
	else
		return list + delimiter + value;
}



/**
 *
 */
Utilities.hideCollidingElements = function(element) {
	/* hides <select> and <applet> objects (for IE only) */
	function hideElement( tagName, overDiv ) {
	  if( Utilities.isMSIE ) {
	    for( var i = 0; i < document.all.tags( tagName ).length; i++ ) { 
	      var obj = document.all.tags( tagName )[i];
	      if( !obj || !obj.offsetParent ) {
	        continue;
	      }
	  
	      // Find the element's offsetTop and offsetLeft relative to the BODY tag.
	      var objLeft   = obj.offsetLeft;
	      var objTop    = obj.offsetTop;
	      var objParent = obj.offsetParent;
	      
	      while( objParent && objParent.tagName && objParent.tagName.toUpperCase() != "BODY" ) {
	        objLeft  += objParent.offsetLeft;
	        objTop   += objParent.offsetTop;
	        objParent = objParent.offsetParent;
	      }
	  
	      var objHeight = obj.offsetHeight;
	      var objWidth = obj.offsetWidth;
	  
	      if(( overDiv.offsetLeft + overDiv.offsetWidth ) <= objLeft );
	      else if(( overDiv.offsetTop + overDiv.offsetHeight ) <= objTop );
	      else if( overDiv.offsetTop >= ( objTop + objHeight ));
	      else if( overDiv.offsetLeft >= ( objLeft + objWidth ));
	      else {
	        obj.style.visibility = "hidden";
	      }
	    }
	  }
	}
	
	hideElement("SELECT", element);
	hideElement("APPLET", element);
	hideElement("EMBED", element);
}



/**
 *
 */
Utilities.showCollidingElements = function(element) {
	/*
	* unhides <select> and <applet> objects (for IE only)
	*/
	function showElement( tagName ) {
	  if( Utilities.isMSIE ) {
		    for( var i = 0; i < document.all.tags( tagName ).length; i++ ) {
	      var obj = document.all.tags( tagName )[i];
	      if( !obj || !obj.offsetParent ) {
	        continue;
	      }
	      obj.style.visibility = "";
	    }
	  }
	}
	
	showElement("SELECT");
	showElement("APPLET");
	showElement("EMBED");
}