How to declare global variables when using the strict mode pragma

Question

It\'s considered good practice to use a self-invoking function to wrap strict mode compliant code, often called the strict mode pragma:

(function(){
  \"use stri         


        

Answer 1

Andrea Giammarchi has a nice technique for doing this, that works across browsers. Define a function in your self-invoking function called globalEval like so:

(function () {
    "use strict";
    function globalEval(data) {
        data = data.replace(/^\s*|\s*$/g, "");
        if (data) {
            var head = document.getElementsByTagName("head")[0] || document.documentElement,
                script = document.createElement("script");
            script.type = "text/javascript";
            script.text = data;
            head.appendChild(script);
            head.removeChild(script);
        }
    }

    // use globalEval to stick variables into the global scope
    globalEval("var myGlobal = 1;");
    // myGlobal === 1
)();
// myGlobal === 1

Or define the globalEval function outside of the self-invoking code if you want to use it in other scopes.