String Extensions JS - Doncho's

(function () {
    if (!String.prototype.contains) {
        String.prototype.contains = function (searchPattern) {
            var patternLen = searchPattern.length;
            for (var i = 0, length = this.length - patternLen; i < length; i++) {
                var isMatch = true;
                for (var j = 0; j < patternLen; j++) {
                    if (searchPattern[j] !== this[i + j]) {
                        isMatch = false;
                        break;
                    }
                }
                if (isMatch) {
                    return true;
                }
            }
        }
    }

    if (!String.prototype.toCharArray) {
        String.prototype.toCharArray = function () {
            return this.split("");
        }
    }

    if (!String.prototype.trimLeft) {
        String.prototype.trimLeft = function () {
            return this.replace(/^\s+/, "");
        }
    }
    if (!String.prototype.trimRight) {
        String.prototype.trimRight = function () {
            return this.replace(/\s+$/, "");
        }
    }

    if (!String.prototype.trim) {
        String.prototype.trim = function () {
            return this.trimLeft().trimRight();
        }
    }

    if (!String.prototype.trimLeftChars) {
        String.prototype.trimLeftChars = function (chars) {
            var regEx = new RegExp("^[" + chars + "]+");
            return this.replace(regEx, "");
        }
    }

    if (!String.prototype.trimRightChars) {
        String.prototype.trimRightChars = function (chars) {

            var regEx = new RegExp("[" + chars + "]+$");
            return this.replace(regEx, "");
        }
    }

    if (!String.prototype.trimChars) {
        String.prototype.trimChars = function (chars) {
            return this.trimLeftChars(chars).trimRightChars(chars);
        }
    }

    if (!String.prototype.htmlEscape) {
        String.prototype.htmlEscape = function () {
            return this.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, "&#39").replace(/ /g,"&nbsp;");
        }
    }
    if (!String.prototype.padLeft) {
        String.prototype.padLeft = function (count, char) {
            char = char || " ";
            if (char.length > 1) {
                return String(this);
            }
            if (this.length >= count) {
                return String(this);
            }
            var str = String(this);
            for (var i = 0, thisLen = str.length; i < count - thisLen; i++) {
                str = char + str;
            }
            return str;
        }
    }

    if (!String.prototype.padRight) {
        String.prototype.padRight = function (count, char) {
            char = char || " ";
            if (char.length > 1) {
                return String(this);
            }
            if (this.length >= count) {
                return String(this);
            }
            var str = String(this);
            for (var i = 0, thisLen = this.length; i < count - thisLen; i++) {
                str += char;
            }
            return str;
        }
    }
})();