Stringオブジェクト、なんちゃって拡張

javascript 
String.prototype.ucFirst = function () {
   return this.substr(0,1).toUpperCase() + this.substr(1,this.length);
};

String.prototype.lcFirst = function () {
   return this.substr(0,1).toLowerCase() + this.substr(1,this.length);
};

String.prototype.isValidUrl = function(){
    return this.match( '^(s?https?:?/?/[-_.!~*?'()a-zA-Z0-9;?/?:?@&=+?$,%#]*)$' );
};

追記

String.prototype.stripScripts = function() {
  return this.replace(new RegExp('<script[^>]*>([\\S\\s]*?)<\/script>', 'img'), '');
}