Inject javascript into a javascript function

Question

I\'ve got a weird question in that I need to inject some javascript into another javascript function. I am using a framework which is locked so I can not change the existing fun

Answer 1

function doSomething() { ... }
var oldVersionOfFunc = doSomething;
doSomething = function() {
    var retVal = oldVersionOfFunc.apply(oldVersionOfFunc, args);
    // your added code here
    return retVal;
}

This seems to provoke an error (Too much recursion)

function doSomething(){ document.write('Test'); return 45; } 
var code = 'myDoSomething = ' + doSomething + '; function doSomething() { var id = myDoSomething(); document.write("Test 2"); return id; }';
eval(code)
doSomething();

This works for me, even if it is ugly.