/************************
 	Helper utilities for use by other JS functions
 	Author: Aaron Curry
 	Version: May 28, 2007
 ************************/

var utils = {
    findParentNode : function (obj) {
    // Returns the parent HTML node
		var parentObj = obj.parentNode;
		while(parentObj.nodeType != 1) {
			parentObj = parentObj.previousSibling;
            if(parentObj == null) {
                return;
            }
		}
		return parentObj;
	},
    
    findChildNode : function (obj) {
    // Returns the child HTML node
		var childObj = obj.firstChild;
		if(!childObj){return null;}
		while(childObj.nodeType != 1) {
			childObj = childObj.nextSibling;
		}
		return childObj;
	},
    
    findPreviousNode : function (obj) {
    // Returns the previous HTML node
		var prevObj = obj.previousSibling;
        if(prevObj == null) {
            return;
        }
		while(prevObj.nodeType != 1) {
			prevObj = prevObj.previousSibling;
            if(prevObj == null) {
                return;
            }
		}
		return prevObj;
	},
    
    findNextNode : function (obj) {
    // Returns the next HTML node
		var nextObj = obj.nextSibling;
        if(nextObj == null) {
            return;
        }
		while(nextObj.nodeType != 1) {
			nextObj = nextObj.nextSibling;
            if(nextObj == null) {
                return;
            }
		}
		return nextObj;
	},
	
	getNodeValue : function(obj,tag) {
		return obj.getElementsByTagName(tag)[0].firstChild.nodeValue;
	},
	
	getElementsByClass : function(searchClass,node,tag) {
	// Returns an array of nodes matching searchClass - cribbed from Dustin Diaz
		var classElements = new Array();
		if ( node == null )
			node = document;
		if ( tag == null )
			tag = '*';
		var els = node.getElementsByTagName(tag);
		var elsLen = els.length;
		var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
		for (i = 0, j = 0; i < elsLen; i++) {
			if ( pattern.test(els[i].className) ) {
				classElements[j] = els[i];
				j++;
			}
		}
		return classElements;
},
	addLoadEvent : function(func) {
  		var oldonload = window.onload;
  		if (typeof window.onload != 'function') {
    		window.onload = func;
  		} else {
    			window.onload = function() {
      				oldonload();
      				func();
    			}
  		}
	}

}