executing anonymous functions created using JavaScript eval()

Question

I have a function and its contents as a string.

var funcStr = "function() { alert('hello'); }";

Now, I do an eval() to actually get that function in a variable.

var func = eval(funcStr);

If I remember correctly, in Chrome and Opera, simply calling

func();

invoked that function and the alert was displayed.

But, in other browsers it wasn't the case. nothing happened.

I don't want an arguement about which is the correct method, but how can I do this? I want to be able to call variable(); to execute the function stored in that variable.

Answer 1

Try

var funcStr = "var func = function() { alert('hello'); }";

eval(funcStr);

func();

Answer 2

Use the eval like this :

var func = eval('(' + funcStr + ')');

Answer 3

How about this?

var func = new Function('alert("hello");');

To add arguments to the function:

var func = new Function('what', 'alert("hello " + what);');
func('world'); // hello world

Do note that functions are objects and can be assigned to any variable as they are:

var func = function () { alert('hello'); };
var otherFunc = func;
func = 'funky!';

function executeSomething(something) {
    something();
}
executeSomething(otherFunc); // Alerts 'hello'

Answer 4

IE cannot eval functions (Presumably for security reasons).

The best workaround is to put the function in an array, like this:

var func = eval('[' + funcStr + ']')[0];

Answer 5

What also works is

var myFunc = function(myParam){
   // function body here
}