Javascript dynamically attaching functions to objects

Question

How to attach a function dynamically to a javascript object.For ex: if the function for dynamic attachment is attach(),then i should be able to attach the function fn to onject obj as follows..

attach(
     obj,fn,{
                  alert(1)
            }
      )


function attach(obj,fnName,code)
{
    obj[fnName] = code;
}

Answer 1

If by "attach a function dynamically to a javascript object" you mean "add a function-object as an object property" then the syntax you've already shown is almost right. This is what it should be:

var fnName = "testFunc";
obj[fnName] = function() { alert("Test function"); };
// or
obj.testFunc = function() { ... };
// or
obj[fnName] = nameOfFunctionDefinedElsewhereInCurrentScope;

Which means you could call your attach() function like this:

// attach an anonymous function:
attach(obj, "newFunctionName", function() { alert(1); });
// attach a function defined elsewhere
attach(obj, "newFunctionName", someFunction);

Note: the attach() function really doesn't save any effort at all, in fact it just gives you more characters to type...

By the way (but don't do this), if the parameter you want to pass as code is a string of code do this:

var code = "alert(0);";
obj[fnName] = new Function(code);

More information: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function