A simple XML to JSON converter. Originally based on http://goo.gl/xfG0l and simplified.

xml2json.js

xml2json = function(xml, extended) {
	var root, out,
	jsVar = function(s) { 
		return String(s || "").replace(/-/g,"_"); 
	},
	isNum = function(s) { 
		return (typeof s === "number") || String((s && typeof s === "string") ? s : "").test(/^((-)?([0-9]*)((\.{0,1})([0-9]+))?$)/);
	},
	myArr = function(o) {
		if (!o.length) {
			o = [ o ];
			o.length = o.length;
		}
		return o;
	};
	
	if (!xml) {
		return;
	}
	
	function parseXML(node, simple) {
		var txt = "", obj = null, att = null,
		nt = node.nodeType, nn = jsVar(node.localName || node.nodeName),
		nv = node.text || node.nodeValue || "";

		if (!node) {
			return; 
		}
		
		if (node.childNodes) {
			if (node.childNodes.length > 0) {
				$.each(node.childNodes, function(n,cn) {
					var cnt = cn.nodeType, cnn = jsVar(cn.localName || cn.nodeName),
					cnv = cn.text || cn.nodeValue || "";
					
					if (cnt === 8) {
						return; 
					} else if (cnt === 3 || cnt === 4 || !cnn) {
						if (cnv.match(/^\s+$/)) {
							return;
						}
						
						txt += cnv.replace(/^\s+/,"").replace(/\s+$/,"");
					} else {
						obj = obj || {};
						
						if (obj[cnn]) {
							if (!obj[cnn].length) {
								obj[cnn] = myArr(obj[cnn]);
							}
							
							obj[cnn][obj[cnn].length] = parseXML(cn, true);
							obj[cnn].length = obj[cnn].length;
						} else {
							obj[cnn] = parseXML(cn);
						}
					}
				});
			}
		}
		
		if (node.attributes) {
			if (node.attributes.length > 0) {
				att = {}; obj = obj || {};
				$.each(node.attributes, function(a,at) {
					var atn = jsVar(at.name), atv = at.value;
					att[atn] = atv;
					if (obj[atn]) {
						if (!obj[atn].length) obj[atn] = myArr(obj[atn]);
						obj[atn][ obj[atn].length ] = atv;
						obj[atn].length = obj[atn].length;
					} else {
						obj[atn] = atv;
					}
				});
			}
		}
		
		if (obj) {
			obj = $.extend( (txt!='' ? new String(txt) : {}), obj || {});
			txt = (obj.text) ? (typeof(obj.text) === "object" ? obj.text : [obj.text || ""]).concat([txt]) : txt;
			if (txt) obj.text = txt;
			txt = "";
		}
		
		var out = obj || txt;
		
		if (extended) {
			if (txt) out = {};
			txt = out.text || txt || "";
			if (txt) out.text = txt;
			if (!simple) out = myArr(out);
		}
		
		return out;
	}
	
	// Convert plain text to xml
	if (typeof xml === "string") {
		// Remove the XML namespaces
		xml = this.string2xml(xml.replace(/\w+:/ig, ""));
	}
	
	// Quick fail if not xml (or if this is a node)
	if (!xml.nodeType) {
		return;
	}
	
	if (xml.nodeType === 3 || xml.nodeType === 4) {
		return xml.nodeValue;
	}
	
	// Find xml root node
	root = (xml.nodeType === 9) ? xml.documentElement : xml;
	
	// Convert XML to JSON
	out = parseXML(root, true);
	
	// Clean-up
	xml = null, root = null;
	delete xml, root;
	
	// Send output
	return out;
}