Javascript urldecode : URLs : PHP functions in JavaScript JAVASCRIPT TUTORIALS

function urldecode( str ) {
    // Decodes URL-encoded string  
    // 
    // version: 901.1411
    // discuss at: http://phpjs.org/functions/urldecode
    // +   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
    // %          note: info on what encoding functions to use from: http://xkr.us/articles/javascript/encode-compare/
    // *     example 1: urldecode('Kevin+van+Zonneveld%21');
    // *     returns 1: 'Kevin van Zonneveld!'
    // *     example 2: urldecode('http%3A%2F%2Fkevin.vanzonneveld.net%2F');
    // *     returns 2: 'http://kevin.vanzonneveld.net/'
    // *     example 3: urldecode('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');
    // *     returns 3: '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'
    
    var histogram = {};
    var ret = str.toString();
    
    var replacer = function(search, replace, str) {
        var tmp_arr = [];
        tmp_arr = str.split(search);
        return tmp_arr.join(replace);
    };
    
    // The histogram is identical to the one in urlencode.
    histogram["'"]   = '%27';
    histogram['(']   = '%28';
    histogram[')']   = '%29';
    histogram['*']   = '%2A';
    histogram['~']   = '%7E';
    histogram['!']   = '%21';
    histogram['%20'] = '+';

    for (replace in histogram) {
        search = histogram[replace]; // Switch order when decoding
        ret = replacer(search, replace, ret) // Custom replace. No regexing   
    }
    
    // End with decodeURIComponent, which most resembles PHP's encoding functions
    ret = decodeURIComponent(ret);

    return ret;
}