function checkExtension(extensionArray, fileName) {
	var thisext = fileName.substr(fieldvalue.lastIndexOf('.'));
	for(var i = 0; i < extensionArray.length; i++) {
		if(thisext == extensionArray[i]) { return true; }
	}
	alert("Your upload form contains an unapproved file name.");
	return false;
}
$.tablesorter.addParser({ 
     // set a unique id 
    id: 'postings', 
    is: function(s) { 
        // return false so this parser is not auto detected 
        return false; 
    }, 
    format: function(s) { 
		var parser = new DOMParser();
		var element = parser.parseFromString('<div>' + s + '</div>', "text/xml");
		var span;
		if ($(element).find('span').length == 2) span = $(element).find('span');
		else span = $(element).find('SPAN');
		//alert(element);
		var sorted = span.eq(1);
		//alert(sorted.text());
		return -sorted.text();
    }, 
    // set type, either numeric or text 
    type: 'numeric' 
}); 
$.tablesorter.addParser({ 
     // set a unique id 
    id: 'aantal', 
    is: function(s) { 
        // return false so this parser is not auto detected 
        return false; 
    }, 
    format: function(s) { 
		var parser = new DOMParser();
		var element = parser.parseFromString('<div>' + s + '</div>', "text/xml");
		if ($(element).find('span').length == 1) span = $(element).find('span');
		else span = $(element).find('SPAN');
		var sorted = span.eq(0);
		//alert(sorted.text());
		return -sorted.text();
    }, 
    // set type, either numeric or text 
    type: 'numeric' 
});      
$.tablesorter.addParser({ 
     // set a unique id 
    id: 'auteur', 
    is: function(s) { 
        // return false so this parser is not auto detected 
        return false; 
    }, 
    format: function(s) { 
		var parser = new DOMParser();
		var element = parser.parseFromString('<div>' + s + '</div>', "text/xml");
		if ($(element).find('span').length == 1) span = $(element).find('span');
		else span = $(element).find('SPAN');
		var sorted = span.eq(0);
		return sorted.text();
    }, 
    // set type, either numeric or text 
    type: 'text' 
});
$.tablesorter.addParser({ 
     // set a unique id 
    id: 'lastauteur', 
    is: function(s) { 
        // return false so this parser is not auto detected 
        return false; 
    }, 
    format: function(s) { 
		return s;
    }, 
    // set type, either numeric or text 
    type: 'text' 
});
$.tablesorter.addParser({ 
     // set a unique id 
    id: 'datum', 
    is: function(s) { 
        // return false so this parser is not auto detected 
        return false; 
    }, 
    format: function(s) { 
		return s;
    }, 
    // set type, either numeric or text 
    type: 'numeric' 
});
$(document).ready(function() {
	if (typeof(DOMParser) == 'undefined') {
		DOMParser = function() {}
		DOMParser.prototype.parseFromString = function(str, contentType) {
			if (typeof(ActiveXObject) != 'undefined') {
				var xmldata = new ActiveXObject('MSXML.DomDocument');
				xmldata.async = false;
				xmldata.loadXML(str);
				return xmldata;
			} else if(typeof(XMLHttpRequest) != 'undefined') {
				var xmldata = new XMLHttpRequest;
				if (!contentType) {
					contentType = 'application/xml';
				}
				xmldata.open('GET', 'data:' + contentType + ';charset=utf-8,' + encodeURIComponent(str), false);
				if (xmldata.overrideMimeType) {
					xmldata.overrideMimeType(contentType);
				}
				xmldata.send(null);
				return xmldata.responseXML;
			}
		}
	}
	if ($('table.onderwerpen')) {
	//if (($('table.onderwerpen')) && (typeof(DOMParser) != 'undefined')) {
		if ($('table.onderwerpen th').length == 6) {
			// gebruiker is ingelogd
			$('table.onderwerpen').tablesorter( {
				headers: { 
					0: {sorter: 'false'}, 
					1: {sorter: 'postings'}, 
					2: {sorter: 'auteur'},
					3: {sorter: 'aantal'},
					4: {sorter: 'lastauteur'},
					5: {sorter: 'datum'}
				} 
			});
		}
		else {
			$('table.onderwerpen').tablesorter( {
				sortList: [[0,0], [1,1], [2,0], [3,1], [4,0]],
				headers: { 
					0: {sorter: 'false'}, 
					1: {sorter: 'postings'}, 
					2: {sorter: 'auteur'},
					3: {sorter: 'lastauteur'},
					4: {sorter: 'datum'}
				}
			} );
		}
	}
});