// Page Init code
function Page_Load() {
    // this uses script to add rounded corners to search dropdown containers.
    //roundCorners('.dd_nav','BtmL,BtmR,TopR')
    roundCorners('#dd_category_nav','BtmL,BtmR,TopR')
    roundCorners('#dd_subject_nav','BtmL,BtmR')
    roundCorners('#dd_sort_nav','BtmL,BtmR')
}

/*
    ************************************************* UTILITY FUNCTIONS vvvvvvvvvvvvvvvvvvvvvvvvvvvv
*/

/// creates and appends DIVs containing round corner gif 
/// based on DOM ID or CSS class.
function roundCorners(objRef,whichCorners){
	objRef = trim(objRef);
	// corner options BtmL, BtmR, TopL, TopR
	allCorners = "BtmL, BtmR, TopL, TopR";
	if(whichCorners==null || trim(whichCorners).length==0)
		whichCorners = allCorners;
	corners = whichCorners.split(',');
	domObj = new Array();
	if(objRef.charAt(0)=='#'){
		domObj[0] = document.getElementById(objRef.substring(1,objRef.length));
	} else if(objRef.charAt(0)=='.') {
		domObj = getElementsByClassName(objRef.substring(1,objRef.length));
	} else {		
		alert('roundCorners Syntax Error: Invalid objRef parameter.\n\n* objRef of a DOM ID must be prefixed with a "#" (pound sign)\n* objRef of a CSS class prefixed with a "." (period)')
		return;
	}	
	
	for(d=0;d<domObj.length;d++) {
	    if(domObj[d]!=null){
		    for(c=0;c<corners.length;c++) {
			    roundCorner=document.createElement("div");
			    roundCorner.className=trim(corners[c]);
			    domObj[d].parentNode.insertBefore(roundCorner, domObj[d]);		
			    domObj[d].appendChild(roundCorner);

		    }
		}
	}	
}

function trim(str) {
// trim whitespace from a string
	s = str.replace(/^(\s)*/, '');
	s = s.replace(/(\s)*$/, '');
	return s+'';
}



/*
    ************************************************* DOM HELPER FUNCTIONS vvvvvvvvvvvvvvvvvvvvvvvvvvvv
*/
function $(id) {
    // shorthand for targeting a document element by name
    if (document.getElementById(id) != undefined) {
        return document.getElementById(id);
    } else {
        return null;
    }
}




/// returns all elements by css class name in entire document, or within specified parent element as well as with specific tag;
/*
parameters:
className : One or several class names, separated by space. Multiple class names demands that each match have all of the classes specified. [Mandatory]. 
tag : Specifies the tag name of the elements to match. [Optional]. 
elm : Reference to a DOM element to look amongst its children for matches. Recommended for better performance in larger documents. [Optional].
*/
var getElementsByClassName = function (className, tag, elm){
	if (document.getElementsByClassName) {
		getElementsByClassName = function (className, tag, elm) {
			elm = elm || document;
			var elements = elm.getElementsByClassName(className),
				nodeName = (tag)? new RegExp("\\b" + tag + "\\b", "i") : null,
				returnElements = [],
				current;
			for(var i=0, il=elements.length; i<il; i+=1){
				current = elements[i];
				if(!nodeName || nodeName.test(current.nodeName)) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	else if (document.evaluate) {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = "",
				xhtmlNamespace = "http://www.w3.org/1999/xhtml",
				namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace)? xhtmlNamespace : null,
				returnElements = [],
				elements,
				node;
			for(var j=0, jl=classes.length; j<jl; j+=1){
				classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";
			}
			try	{
				elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);
			}
			catch (e) {
				elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);
			}
			while ((node = elements.iterateNext())) {
				returnElements.push(node);
			}
			return returnElements;
		};
	}
	else {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = [],
				elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),
				current,
				returnElements = [],
				match;
			for(var k=0, kl=classes.length; k<kl; k+=1){
				classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));
			}
			for(var l=0, ll=elements.length; l<ll; l+=1){
				current = elements[l];
				match = false;
				for(var m=0, ml=classesToCheck.length; m<ml; m+=1){
					match = classesToCheck[m].test(current.className);
					if (!match) {
						break;
					}
				}
				if (match) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	return getElementsByClassName(className, tag, elm);
};

//set a page init handler, preserving any already existing:
function addLoadEvent(func) {
    if (window.attachEvent) {
        //IE and Opera
        window.attachEvent("onload", func);
    } else if (document.addEventListener != null) {
        //Mozilla
        document.addEventListener("DOMContentLoaded", func, false);
    } else {
        // others/old browsers
        var oldonload = window.onload;
        window.onload = function() {
            if (typeof window.onload == 'function') {
                oldonload();
            }
            func();
        }
    }
}


addLoadEvent(Page_Load);