javascriptjqueryanonymous-functioniife

What is this unknown JavaScript syntax?

Is this jQuery code

(function(jQuery){
})(jQuery);

equivalent to

$(document).ready(function () {
});

If yes, what are the differences between the two? If not, what does the first do?

Solution

  • Absolutely not, the first one is a self-executing anonymous function and the second is the ready handler.

    (function(jQuery){
  //jQuery in this scope is referencing whatever is passed-in
})(jQuery);

    So, the jQuery inside of the function isn't necessarily the same jQuery outside the function. But you typically do not want to mix-n-match global variable names with local ones.

    Take this example:

    (function(obj) {
   alert(obj);
})('Hello');

    This defines a function, then immediately invokes it, passing in "Hello"