This js script simulates Drupal pathauto module that generates an automatic url based on a node title. It is useful for web crawling, testing, ...

pathautojs.js

String.stopWords = 'a,an,as,at,before,but,by,for,from,is,in,into,like,of,off,on,onto,per,since,than,the,this,that,to,up,via,with';

String.escapeRegExp = function(str) {
    return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&");
};

String.prototype.replaceAll = function (find, replace) {
    return this.replace(new RegExp(String.escapeRegExp(find), 'g'), replace);
};

String.prototype.ltrim = function () {
    return this.replace(/^\s+/, "");
};

String.isStopWord = function (word) {
    var regex = new RegExp("\\b" + word + "\\b", "i");
    if (String.stopWords.search(regex) < 0) {

        return false;
    } else {
        return true;
    }
};

String.prototype.removeStopWords = function () {
    words = [];

    this.replace(/\b[^ ]+[\b]?/g,
        function ($0) {
            if (!String.isStopWord($0)) {
                words[words.length] = $0.trim();
            }
        }
    );

    return words.join(" ");
};

String.prototype.pathauto = function() {
    var expected_path = this.toLowerCase();
    expected_path = expected_path.replace(new RegExp("[()&!+`\.\:;]+", 'g'), ""); 
    expected_path = expected_path.replace(new RegExp("[\|{}]+", 'g'), ""); 
    expected_path = expected_path.replace(new RegExp("[\[]+", 'g'), ""); 
    expected_path = expected_path.replace(new RegExp("\]", 'g'), ""); 

    expected_path = expected_path.replace(new RegExp(",", 'g'), ""); 
    expected_path = expected_path.replace(new RegExp("[\+=*%\^\$#@!~\?<>/]+", 'g'), ""); 
    expected_path = expected_path.replace(new RegExp("[\\\\]+", 'g'), ""); 

    expected_path = expected_path.replaceAll("—", "EMPHASIZEDHYPHEN1"); 
    expected_path = expected_path.replaceAll("–", "EMPHASIZEDHYPHEN2"); 
    expected_path = expected_path.removeStopWords(); 
    expected_path = expected_path.replace(new RegExp("[ ]+", 'g'), " "); 
    expected_path = expected_path.ltrim(); 
    expected_path = expected_path.replaceAll(" ", "-"); 
    expected_path = expected_path.replaceAll("EMPHASIZEDHYPHEN1", "%E2%80%94"); 
    expected_path = expected_path.replaceAll("EMPHASIZEDHYPHEN2", "%E2%80%93"); 
    expected_path = expected_path.substr(0, 87); 

    return expected_path;
};

Taking some ideas from:
https://github.com/mirzaasif/JS-StopWord/blob/master/StopWord.js