Solved

Rewriting 3 Simple Utility Functions in jQuery

Posted on 2010-08-15
3
394 Views
Last Modified: 2012-05-10
Hi All,

I'm using jQuery in a new project and wanted to re-write 3 simple utility functions using jQuery.

1. I have a handy function that I use everywhere called "isDef(arg, argType)" which checks if the argument is null or undefined, (or if "argType" is defined, is of type "argType"). Could you rewrite this using jQuery for me please?

2. I have another handy function called "el(id)" which is an exception-safe wrapper for "getElementById". Could you also rewrite this using jQuery for me please?

3. And lastly I have another handy function called "findParent(elem, type, id)" which finds the nearest parent element of elem which of the specified type and (if defined), has the specified "id". Could you also rewrite this using jQuery for me please?

I have included my orginal code for these 3 functions below:

Thanks in Advance.



// MY ORIGINAL CODE

function isDef(arg, argtype)
{
 try
 {
  if (argtype === null || typeof(argtype) == 'undefined') return (arg !== null && typeof(arg) != 'undefined');
  return (arg !== null && typeof(arg) == argtype);  }  catch (e) {}  return false; }

function el(id)
{
 try
 {
  if (!isDef(id, 'string') || id == '') return null;
  return document.getElementById(id);
 }
 catch(e) {}

 return null;
}

function findParent(elem, type, id)
{
 try
 {
  if (!isDef(elem) || !isDef(type, 'string') || type == '') return null;
  if (!isDef(id)) id = '';

  type = type.toUpperCase();

 var parent = (elem.parentNode ? elem.parentNode : (elem.parent ? elem.parent : NULL));
  while (isDef(parent) && (parent.nodeType != 1 || (parent.nodeName.toUpperCase() != type && (id == '' || id != parent.id))))
   parent = (parent.parentNode ? parent.parentNode : (parent.parent ? parent.parent : NULL));  // Select the parent of the specified type by iterating up the ancestor hiearchy
 
 if (isDef(parent)) return parent;
 }
 catch(e) {}

 return null;
}

Open in new window

0
Comment
Question by:NetSoftDS
3 Comments
 
LVL 75

Expert Comment

by:Michel Plungjan
ID: 33445431
el() = $()


0
 
LVL 42

Accepted Solution

by:
David S. earned 500 total points
ID: 33446724
jQuery is a JavaScript library, not a separate language, so there isn't always a reason to rewrite other utility functions you use to use it.  There's no need to rewrite your isDef() function.

As Michel said, $() will work in place of el(), except you would need to use "#" at the beginning of a string passed to it, if you wanted to use an ID. (Many other selectors can be used in addition to just IDs: http://api.jquery.com/category/selectors/ )

For the findParent() function, I would suggest not using it all and just use jQuery, otherwise you'd lose the ability to use jQuery's "chaining" feature.

In jQuery to get the...

parent:
  $('selector').parent()

first ancestor of a certain type:
  $('selector').parents('ul').eq(0)

ancestor with a certain ID:
  $('selector').parents('#someID').eq(0)
0
 

Author Closing Comment

by:NetSoftDS
ID: 33507708
Thanks
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this article you'll learn how to use Ajax calls within your CodeIgniter application. To explain this, I'll illustrate how to implement a simple contact form to allow visitors to send you an email through your web site.
This article discusses how to create an extensible mechanism for linked drop downs.
The viewer will learn the basics of jQuery including how to code hide show and toggles. Reference your jQuery libraries: (CODE) Include your new external js/jQuery file: (CODE) Write your first lines of code to setup your site for jQuery…
Video by: Mark
This lesson goes over how to construct ordered and unordered lists and how to create hyperlinks.

713 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question