CODEWITHSUNDEEP
javascriptxmlhttprequestgetelementsbyclassname
user1197573
user1197573

Reputation: 21

Javascript object/function not working when calling DOM

I'm very beginner so I'm sorry if something doesn't make sense :)

I'm trying to search an XML DOM by ClassName, using a custom function which only seems to work when I'm searching the document the script is in.

This is the function:

Object.prototype.getElementsByClassName = function(getElementsByClass) {

function getElementsByClass(searchClass,node,tag) {

    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;

}

xmlhttp=new XMLHttpRequest();

xmlhttp.open("GET","somexml.xml",false);

xmlhttp.send();

xmlDoc=xmlhttp.responseXML;

var foo = xmlDoc.getElementsByClassName("gridCellAlt");

(I then output foo somewhere down later - the output all works fine.)

Now, everything works if I use xmlDoc.getElementsByTagName and use a tag name - however, the page I am going to be accessing makes use of class names, so I want to use xmlDoc.getElementsByClassName. The above script works completely fine if I use var foo = document.getElementsByClassName("gridCellAlt"); and include the information I am accessing in the page running the script, but when I try to use it on the xmlDoc DOM it doesn't work. To sum it up: the only time the script doesn't work is when I'm using the xmlDoc (instead of document), and the getElementsbyClassName in conjunction. If I use document and getElementsByClassName its fine. If I use xmlDoc and get elementsByTagName its fine.

I'm thinking the getElementsByClassName isn't searching within the DOM nodes correctly, but even if I put class="gridCellAlt" somewhere in the root node of a test DOM it still doesn't find it. I've tried adding more information behind foo = xmlDoc.getElementsByClassName("gridCellAlt", (info here)) but that doesn't seem to address the issue either.

Upvotes: 2

Views: 299

Answers (1)

mgraph
mgraph

Reputation: 15338

xmlhttp.onreadystatechange = function(){
        if(xmlhttp.readyState == 4){
            xmlDoc=xmlhttp.responseXML;
            var foo = xmlDoc.getElementsByClassName("gridCellAlt");
        }
    }

Upvotes: 2

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