jQuery page load

I see people using all these different techniques with jQuery. I know the 2nd technique will run on page load. But when will the 1st and the 3rd functions fire? The third technique is used in plugins to avoid conflict r开发者_开发知识库ight? But that will fire before page load surely? I also added a 4th technique. I would like to know when you should/shouldn't use each technique. And if any of them are bogus let me know!

1st

(function($) {

})(jQuery);

2nd

$(document).ready(function(){

});

3rd

$(function(){

}());

4th

jQuery(function($) { 

}); 

5th

(function(){

})();

---

Update He's changed the list of calls in the question, so I'm updating to match.

The first is a hack to avoid conflicts with other libraries which might assign $. It is not a ready handler. The second and third are ready event handlers.

From the jQuery API reference:

All three of the following syntaxes are equivalent:

• $(document).ready(handler)
• $().ready(handler) (this is not recommended)
• $(handler)

So although these three do the same thing, avoid the second.

In jQuery 1.3, $() was equal to $(document). This is no longer true in 1.4.

The fourth looks like a syntax error to me. It essentially assigns a new ready handler, but it passes a function with an argument called $. Since this is an event handler, jQuery will pass event info in the first argument. You don't typically want $ to represent event info.

The fifth defines a new function and then invokes it immediately, passing no arguments. So this:

(function(){
    alert("Hi!");
})();

Means the same as this:

alert("Hi!");

---

1st - assigns the $ to jQuery for use only inside the brackets (no conflict version) 2nd is normaln version and 3rd is shorthand :)

more: http://docs.jquery.com/Using_jQuery_with_Other_Libraries#Overriding_the_.24-function

Edit: Oh yes, the shorthand is:

$(function() {
  // your code
});

(no parenthesis after function() brackets)

Edit: After longer reading my own link, it seems, that the first one may only wrap part of code, where $ symbol is assigned to jQuery, but you still have to use $(document).ready()

Edit:As for updated list: 5th type: check the other answer, I did not know about that type.

jQuery(function($){

});

The 4th, however, is used for: 1., attach $ to jQuery, temporarily overloading (inside brackets) any framework, that has $ shorthand in use globaly (i.e. prototype) and ALSO is document.ready statement.