jQuery pitfalls to avoid [closed]

Answer 1

Using ClientID to get the "real" id of the control in ASP.NET projects.

jQuery('#<%=myLabel.ClientID%>');

Also, if you are using jQuery inside SharePoint you must call jQuery.noConflict().

Answer 2

Use strings accumulator-style

Using + operator a new string is created in memory and the concatenated value is assigned to it. Only after this the result is assigned to a variable. To avoid the intermediate variable for concatenation result, you can directly assign the result using += operator. Slow:

a += 'x' + 'y';

Faster:

a += 'x';
a += 'y';

Primitive operations can be faster than function calls

Consider using alternative primitive operation over function calls in performance critical loops and functions. Slow:

var min = Math.min(a, b);
arr.push(val);

Faster:

var min = a < b ? a : b;
arr[arr.length] = val;

Read More at JavaScript Performance Best Practices

Answer 3

Pitfall: Using loops instead of selectors.

If you find yourself reaching for the jQuery '.each' method to iterate over DOM elements, ask yourself if can use a selector to get the elements instead.

More information on jQuery selectors:
http://docs.jquery.com/Selectors

Pitfall: NOT using a tool like Firebug

Firebug was practically made for this kind of debugging. If you're going to be mucking about in the DOM with Javascript, you need a good tool like Firebug to give you visibility.

More information on Firebug: http://getfirebug.com/

Other great ideas are in this episode of the Polymorphic Podcast: (jQuery Secrets with Dave Ward) http://polymorphicpodcast.com/shows/jquery/