javascript - What's a more secure alternative for eval() when I just want to call a function? - Stack Overflow

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I know PHP has call_user_func, I was just wondering if JavaScript had something similar, where the method I want to call is, for example: object.set$fieldID($fieldValue)

I would rather not go through if/else/switch blocks just to execute one line of code properly.

If it helps, I am using jQuery.

I know PHP has call_user_func, I was just wondering if JavaScript had something similar, where the method I want to call is, for example: object.set$fieldID($fieldValue)

I would rather not go through if/else/switch blocks just to execute one line of code properly.

If it helps, I am using jQuery.

• javascript
• eval

Share Improve this question Follow edited Jul 29, 2009 at 10:03 soulmerge 75.8k2020 gold badges121121 silver badges160160 bronze badges asked Jul 29, 2009 at 9:47 Will MorganWill Morgan 4,49055 gold badges3030 silver badges4242 bronze badges

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2 Answers 2

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object["set" + $fieldID]($fieldValue);

Some reading material for the above: Member Operators on MDC.

Some advanced methods include Function.prototype.call and Function.prototype.apply. The first is somehow equivalent to PHP's call_user_func() while the latter is somehow equivalent to PHP's call_user_func_array().

The difference between PHP's functions and JavaScript's is that JavaScript allows you to call methods of some object in the context of another object. This is done through the use of the first argument of call() and apply().

An equivalent for the above example, but using call() and apply() looks like this:

object["set" + $fieldID].call(object, $fieldValue);
object["set" + $fieldID].apply(object, [$fieldValue]);

The first argument must be object otherwise the method will be executed with the this pointer bound to the global object, window in the case of browsers.

@lonut is correct. More generally though, if you want to call functions that aren't a part of an explicit object (e.g.: global), you can call them on the window object:

var foo = function() { alert(1); };
window['foo']();

since all objects are contained in window.

Another example:

var object = function() { this.method = function() { alert(2); }; }
var instance = new object();
window['instance']['method']();

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