JQuery

Posts about using the JavaScript framework JQuery.

Checking If An Element Exists In jQuery

Sunday, February 3, 2013 - 18:32

To verify that an element exists in the DOM you just need to use the .length property of a jQuery lookup. If the element is there then the number of elements found will be greater than 0.

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Easy QR Code Generation With Google Charts API

Thursday, April 26, 2012 - 10:29

When I found about the ability to create QR codes using the Google Charts API I decided to sit down and create a little tool that would generate QR codes for me. I've had this tool for a while and I recently noticed that the QR code mechanism has become depricated. The API will still work for a couple of years so I thought it was worth posting this. Creating a static QR code using Google Charts is quite easy, all you need to do is create an image. For instance, to create a QR code for the #! code address I would do the following.

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Prevent Enter Key Submitting Forms With JQuery

Friday, July 15, 2011 - 10:35

A common practice that some users have is to press the enter key when they are filling in forms on the web. This might be when they are just moving to the next field, but the trouble is that this will submit the form.

To prevent this from happening you can simply stop the form being submitted if the enter key had been pressed. This is done by binding a JQuery event to the input elements of the form and returning false if the key pressed is enter, which has the keyCode value of 13. We also include a call to the JQuery method preventDefault() to stop the event propagating.

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Using jQuery To Load Content Onto A Page Without An iFrame

Tuesday, February 8, 2011 - 23:20

iFrames can be a convinent way of loading content from one domain onto another, but they do have their limitations. For example, it usually isn't possible to style the contents of the iFrame and you are therefore left at the mercy of a third party site. They also look pretty shonky if the third party site does down for whatever reason. Displaying large "page not found" statements on your page is quite unsightly.

There is a function in jQuery called load() that will use an AJAX request to load content from page onto another, and can even extract specific areas of the page and return only those parts. I thought I would run through some examples and then show how it is possible to display content from another domain on a page. Lets say we have a PHP file on the server that generates a random number, this would be the following very simple code.

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Enabling The Use Of delay() In Pre jQuery 1.4

Monday, January 24, 2011 - 13:58

The other day I was trying to convert a HTML template into a CMS system and I found a stumbling block with the use of the jQuery function delay() in the template's JavaScript. During part of the templating process I found the following error occurring on the page.

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Using JQuery To Open External Links In A New Window

Friday, February 19, 2010 - 10:17

Opening external links in a new window can be useful, but adding target="_blank" can be a real chore. Not only that, but if you are trying to validate the page to XHTML strict then the target attribute will cause errors to appear as it is not defined in XHTML.

An easy solution to this issue is to add the following JQuery to your site. It will look for any links that start with http and do not contain the current domain and add a new click event to them that causes a new window to be opened. This will exclude most links straight away as they will most likely be relative.

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