Global variable is logged as undefined when passed as parameter to setTimeout callback function

Alternatively you can do it without creating a closure.

function myFunction(str1, str2) {  alert(str1); //hello  alert(str2); //world}window.setTimeout(myFunction, 10, 'hello', 'world');

But note it doesn't work on IE < 10 according to MDN.

When setTimeout invokes the callback, it doesn't pass any arguments (by default); that is, the argument x is undefined when the callback is invoked.

If you remove the parameter x, x in the function body won't refer to the undefined parameter but instead to the variable you defined outside the call to setTimeout().

var x = "hello";setTimeout(function () { //note: no 'x' parameter    console.log("setTimeout ... : " + x);}, 1000);

Alternatively, if it must be a parameter, you can pass it as an argument to setTimeout (do yourself a favor and name it differently, though):

var x = "hello";setTimeout(function (y) {    console.log("setTimeout ... : " + y);}, 1000, x);

Ran into this myself and looked at the Node docs, arguments to be passed into the function come in as a 3rd(or more) parameter to the setTimeout call so...

myfunc = function(x){console.log(x)};x = "test";setTimeout(myfunc,100,x);

Worked for me.