Winn.ws » Javascript

.live() and the future

Greg Winn — Sun, 18 Apr 2010 06:25:40 +0000

Just recently i seen this used by a co-worker, and did not know much about this. So I took some time and looked it up on the jQuery site docs. I was amazed by what it does, the .live() function will match any element now and in the future! This means if you .load() a remote page in the .live() can match an element on that page as it’s loaded in!

Attach a handler to the event for all elements which match the current selector, now or in the future. jQuery – .live()

Some info on .live()
his method is a variation on the basic .bind() method for attaching event handlers to elements. When .bind() is called, the elements that the jQuery object refers to get the handler attached; elements that get introduced later do not, so they would require another .bind() call. For instance, consider the HTML:


  
    Click here

We can bind a simple click handler to this element:

$('.clickme').bind('click', function() {
  // Bound handler called.
});

When the element is clicked, the handler is called. However, suppose that after this, another element is added:

$('body').append('Another target
');

This new element also matches the selector .clickme, but since it was added after the call to .bind(), clicks on it will do nothing.

The .live() method provides an alternative to this behavior. If we bind a click handler to the target element using this method:

$('.clickme').live('click', function() {
  // Live handler called.
});

And then later add a new element:

$('body').append('Another target
');

Then clicks on the new element will also trigger the handler.

Cookies with JQuery

Greg Winn — Tue, 10 Feb 2009 05:16:32 +0000

So in some of my latest projects i dont have full source access, so i need to look for cookies the main application is setting. To do this i am using jQuery to look into the cookies and give me the value. Once i know the value i can then write a new cookie that the main application will see and use.

Below is an idea of what i am doing to read the cookies from the main application.

if($.cookie('Cookie_name')) {
     var MainAppCookie = $.cookie('Cookie_name');
     $.cookie('NewCookie_' + MainAppCookie , 'Value');
}

To use the $.cookie i am using a simple plugin for jQuery. This allows me to access the cookies quick and easy. Now if the application gives me a special cookie i can then delete my old ones by doing this…

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if($.cookie('Cookie_name') == 'Special Text') {
     $.cookie('MyCookie', null, {-1}); // This will delete the cookie
}

The OO way of JavaScript

Greg Winn — Tue, 28 Oct 2008 15:00:51 +0000

This is something I picked up in making my own functions and trying not to effect my other js libraries. I first start by creating a base function like so:

function Wrapper() {
 
}

Then inside that function I create my “methods” if you will…

function Wrapper() {
     this.MyMethod = function(var) {
          return var;
     }
}

Once I am done creating the methods I now need to call my new javascript methods, I can do this by creating a new instance of my function that wraps the methods.

var MyScript = new Wrapper();

After creating the new instance I can now call my methods.

MyScript.MyMethod('Some Text');