function urlencode (str) {
    // http://kevin.vanzonneveld.net
    // +   original by: Philip Peterson
    // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +      input by: AJ
    // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Brett Zamir (http://brett-zamir.me)
    // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +      input by: travc
    // +      input by: Brett Zamir (http://brett-zamir.me)
    // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Lars Fischer
    // +      input by: Ratheous
    // %          note 1: info on what encoding functions to use from: http://xkr.us/articles/javascript/encode-compare/
    // *     example 1: urlencode('Kevin van Zonneveld!');
    // *     returns 1: 'Kevin+van+Zonneveld%21'
    // *     example 2: urlencode('http://kevin.vanzonneveld.net/');
    // *     returns 2: 'http%3A%2F%2Fkevin.vanzonneveld.net%2F'
    // *     example 3: urlencode('http://www.google.nl/search?q=php.js&ie=utf-8&oe=utf-8&aq=t&rls=com.ubuntu:en-US:unofficial&client=firefox-a');
    // *     returns 3: 'http%3A%2F%2Fwww.google.nl%2Fsearch%3Fq%3Dphp.js%26ie%3Dutf-8%26oe%3Dutf-8%26aq%3Dt%26rls%3Dcom.ubuntu%3Aen-US%3Aunofficial%26client%3Dfirefox-a'

    var hash_map = {}, unicodeStr='', hexEscStr='';
    var ret = (str+'').toString();

    var replacer = function (search, replace, str) {
        var tmp_arr = [];
        tmp_arr = str.split(search);
        return tmp_arr.join(replace);
    };

    // The hash_map is identical to the one in urldecode.
    hash_map["'"]   = '%27';
    hash_map['(']   = '%28';
    hash_map[')']   = '%29';
    hash_map['*']   = '%2A';
    hash_map['~']   = '%7E';
    hash_map['!']   = '%21';
    hash_map['%20'] = '+';
    hash_map['\u00DC'] = '%DC';
    hash_map['\u00FC'] = '%FC';
    hash_map['\u00C4'] = '%D4';
    hash_map['\u00E4'] = '%E4';
    hash_map['\u00D6'] = '%D6';
    hash_map['\u00F6'] = '%F6';
    hash_map['\u00DF'] = '%DF';
    hash_map['\u20AC'] = '%80';
    hash_map['\u0081'] = '%81';
    hash_map['\u201A'] = '%82';
    hash_map['\u0192'] = '%83';
    hash_map['\u201E'] = '%84';
    hash_map['\u2026'] = '%85';
    hash_map['\u2020'] = '%86';
    hash_map['\u2021'] = '%87';
    hash_map['\u02C6'] = '%88';
    hash_map['\u2030'] = '%89';
    hash_map['\u0160'] = '%8A';
    hash_map['\u2039'] = '%8B';
    hash_map['\u0152'] = '%8C';
    hash_map['\u008D'] = '%8D';
    hash_map['\u017D'] = '%8E';
    hash_map['\u008F'] = '%8F';
    hash_map['\u0090'] = '%90';
    hash_map['\u2018'] = '%91';
    hash_map['\u2019'] = '%92';
    hash_map['\u201C'] = '%93';
    hash_map['\u201D'] = '%94';
    hash_map['\u2022'] = '%95';
    hash_map['\u2013'] = '%96';
    hash_map['\u2014'] = '%97';
    hash_map['\u02DC'] = '%98';
    hash_map['\u2122'] = '%99';
    hash_map['\u0161'] = '%9A';
    hash_map['\u203A'] = '%9B';
    hash_map['\u0153'] = '%9C';
    hash_map['\u009D'] = '%9D';
    hash_map['\u017E'] = '%9E';
    hash_map['\u0178'] = '%9F';

    // Begin with encodeURIComponent, which most resembles PHP's encoding functions
    ret = encodeURIComponent(ret);

    for (unicodeStr in hash_map) {
        hexEscStr = hash_map[unicodeStr];
        ret = replacer(unicodeStr, hexEscStr, ret); // Custom replace. No regexing
    }

    // Uppercase for full PHP compatibility
    return ret.replace(/(\%([a-z0-9]{2}))/g, function (full, m1, m2) {
        return "%"+m2.toUpperCase();
    });
}

var courseSearch={

	urlRoot: '/courseSearch.php',
	subject: '',
	aMode: '',
	sDate: '',
	dateDefault: '<option value="0">Start Date</option>',
	courseDefault: '<option value="0">Set Search Filters</option>',
	previousSubject: 0,

	init:function() {
		$("courseSubjectFilter").observe('change', function() {
			this.getDropdownOptions();
			this.toggleCourseButton();
			this.previousSubject = $("courseSubjectFilter").value;
		}.bind(courseSearch));

		$("attendanceModeFilter").observe('change', function() {
			this.getDropdownOptions();
			this.toggleCourseButton();
		}.bind(courseSearch));

		$("startDateFilter").observe('change', function() {
			this.getDropdownOptions();
			this.toggleCourseButton();
		}.bind(courseSearch));

		$("courseListSelect").observe('change', function() {
			this.getDropdownOptions();
			this.toggleCourseButton();
		}.bind(courseSearch));
	},

	getDropdownOptions:function() {
		var qString = '?';
		if ($("courseSubjectFilter").value > 0) {qString+= "courseSubject=" + $("courseSubjectFilter").value + '&previousSubject=' + this.previousSubject;}
		if ($("attendanceModeFilter").value > 0) {qString+= '&' + "attendanceMode=" + $("attendanceModeFilter").value;}
		if ($("startDateFilter").value > 0) {qString+= '&' + "startDate=" + $("startDateFilter").value;}
		if ($("courseListSelect").value > 0) {qString+= '&' + "courseSelected=" + $("courseListSelect").value;}
//prompt('url', this.urlRoot + qString);
		new Ajax.Request(this.urlRoot + qString, {
			method: 'get',
			onSuccess: function(transport) {
				coursePos = transport.responseText.indexOf('[#CourseStart#]');
				modePos = transport.responseText.indexOf('[#ModeStart#]');
				datePos = transport.responseText.indexOf('[#DateStart#]');

				if (coursePos != -1) {
					$("courseList").innerHTML = transport.responseText.substring(coursePos + 15, transport.responseText.indexOf('[#CourseEnd#]'));
					$("courseListSelect").observe('change', function() {
						this.getDropdownOptions();
						this.toggleCourseButton();
					}.bind(courseSearch));
				}
				if (modePos != -1) {
					$("attendanceModeSelect").innerHTML = transport.responseText.substring(modePos + 13, transport.responseText.indexOf('[#ModeEnd#]'));
					$("attendanceModeFilter").observe('change', function() {
						this.getDropdownOptions();
						this.toggleCourseButton();
					}.bind(courseSearch));
				}
				if (datePos != -1) {
					$("startDateSelect").innerHTML = transport.responseText.substring(datePos + 13, transport.responseText.indexOf('[#DateEnd#]'));
					$("startDateFilter").observe('change', function() {
						this.getDropdownOptions();
						this.toggleCourseButton();
					}.bind(courseSearch));
				}
			}
		});

	},

	toggleCourseButton:function(newAction) {
		if ($("courseSubjectFilter").value != 0) {
			$("courseFinderButton").disabled = false;
			$("courseFinderButton").style.backgroundPosition = "0px 0px";
			var URL = '/getCourseUrl.php?courseId=' + $("courseListSelect").value + "&subject=";
			URL += urlencode($("courseSubjectFilter").options[+$("courseSubjectFilter").selectedIndex].innerHTML) + "&subjectId=" + $("courseSubjectFilter").value;
			if ($("attendanceModeFilter").value > 0) {URL+= '&' + "attendanceMode=" + $("attendanceModeFilter").value;}
			if ($("startDateFilter").value > 0) {URL+= '&' + "startDate=" + $("startDateFilter").value;}
			new Ajax.Request(URL, {
				method: 'get',
				onSuccess: function(transport) {
					$("courseFinderButton").observe('click', function() {
						document.getElementById("goToCourse").action = transport.responseText;
						$("goToCourse").submit();
					});
				}
			});
		} else {
			$("courseFinderButton").disabled = true;
			$("courseFinderButton").style.backgroundPosition = "0px -64px";
		}
	}
}

Event.observe(window, 'load', function() {
	if ($("courseSubjectFilter")) {
		courseSearch.init();
	}
});