IE7/8 JavaScript method shims using underscore.js

underscore.ie.shim.js

(function() {
  
  function extendPrototype(Obj) {
    return function(method, fn) {
      if (!(method in Obj.prototype)) Obj.prototype[method] = _.isFunction(fn) ? fn : function() {
        return _[method].apply(null, [this].concat(_.toArray(arguments)));
      };
    }
  };
  
  _.each(["indexOf", "lastIndexOf", "forEach", "map", "filter", "every", "some"], extendPrototype(Array));
  extendPrototype(Function)("bind");
  extendPrototype(String)("trim", function() {
    return this.replace(/^\s+/, '').replace(/\s+$/, '');
  });
  
}());