The missing Javascript prototypes.

Javascript is missing some prototypes, and so is jQuery.
The following relate to strings, and are heavily inspired by Java methods. This is what I use to trim strings and clean strings of HTML entities.

String.prototype.othertrim = function() {
    return this.replace(/^\s+|\s+$/g, "");
};
String.prototype.endsWith = function(suffix) {
    return this.indexOf(suffix, this.length - suffix.length) !== -1;
};
String.prototype.fulltrim=function(){
    return this.replace(/(?:(?:^|\n)\s+|\s+(?:$|\n))/g,'').replace(/\s+/g,' ');
};
String.prototype.replaceHtmlEntites = function() {
    var s = this;
    var translate_re = /&(nbsp|amp|quot|lt|gt);/g;
    var translate={"nbsp":" ","amp":"&","quot":"\"","lt":"<","gt":">"};
    return(s.replace(translate_re, function(match, entity) {
        return(translate[entity]);
    }) );
};

These are for jQuery. The first is a POST method that is similar to $.getJSON. The other tells you if a tag exists. You can then do a $('#tagcheck').exists(); and it will return 0 if the tag is not present.

$.postJSON = function (url, data, callback) {
   $.post(url, data, callback, "json");
};
jQuery.fn.exists = function(){return this.length>0;}