javascript - 如何更改 new Function(...) 的全局上下文？

Question

我想指定给定函数的全局上下文，同时保持其本地范围不变。经过一些research结果很接近并且有些工作:

// that iframe is created via document.write to share objects 
var iFrameGlobal = myIFrameGlobal;

(function( ns ) {
  var context = this; // is the iframe's global, correct!
}( iFrameGlobal ));

现在如前所述，我想完整保留该 iframe 上下文中函数的作用域:

 var realGlobal = window;// the creator source of the iframe

 var iFrameGlobal = myIFrameGlobal;


(function( ns ) {


  // is the iframe's global, correct!
  var context = this; 

  // button is a custom HTML element in the iFrame, its owner document    
  // is correct. Its basically a custom widget, its JS has been parsed   
  // in that iframe as well.
  var myWidget = button;

  //the content of the new function 
  var script = "var context = window; console.dir(context); return context"; 

  var fn = new Function("{" + script + "}");

  var result = fn.apply(myWidget, _args || {});//returns realGlobal      


}( iFrameGlobal ));

正如您所看到的，更改全局上下文确实有效，但是当解析新函数时，上下文确实回退到其父文档。

这是故意的吗？我还看到了这个答案 here其中提到了这种行为，但对我来说没有意义，因为“this”是正确的，并且下面的函数应该遍历到它。

ps:

• 已针对 Firefox-29 和 Firebug 1.12 进行了测试(必须在其中运行)
• 实际上，我想在该 iframe 中运行包含 $('#otherButton').css(...) 的“脚本”，通过 fn.apply(myWidget,...) 传递的自定义范围内；

Answer 1

要将函数绑定(bind)到上下文，您必须使用bind(object)。

 var realGlobal = window;// the creator source of the iframe

 var iFrameGlobal = myIFrameGlobal;


(function( ns ) {


  // is the iframe's global, correct!
  var context = this; 

  // button is a custom HTML element in the iFrame, its owner document    
  // is correct. Its basically a custom widget, its JS has been parsed   
  // in that iframe as well.
  var myWidget = button;

  //the content of the new function 
  var script = "var context = window; console.dir(context); return context"; 

  var fn = new Function("{" + script + "}").bind(this);

  var result = fn.apply(myWidget, _args || {});//returns realGlobal      


}( iFrameGlobal ));