Dollar $ in Javascript

[mparker1113]

I have some new code that i am responsible for, and do not know what the $ does in javascript. Can someone enlighten me in this ?

For example, see the code below:

function shiptostateChange(shipgroup, isUpgradedShippingExempt)
{
        // If the business unit is UK, disable the shipping method box if country is changed to anything else
        // If the business unit is US, disable the shipping method boxes if country is changed to anything else
        
        stateChange($("State" + shipgroup), shipgroup)      
	    disableExpress($('Country' + shipgroup),shipgroup,isUpgradedShippingExempt)
	        
}
what are the dollar symbols? Are they ajax related ?

(Thank you)

[A1ien51]

libraries such as Prototype.js and jQuery use $ to represent getElementById()

Look at what library is being used on the page and look at the documentation for it.

Eric

[Kostas Zotos]

Hi,

The dollar symbol usually found on regular expressions (eg. as back-reference for a match found in a string ).
Here is a function named: $ and used to getElementById() (as already reported)
(search the code for a function with this name)

Cheers!

Kostas

[seatoskyhk]

I had this quesiton b4 and now I understand too.

usually, people use $ for two reasons (as far as i know, please correct me if wrong)
1) able to port to a PHP script
2) jQuery's convention of using $ for function / var name.

[Declan1991]

Prototype had it first (their $ function is quite handy, it accepts either id strings or elements and returns an array). Everyone else thought it was a good idea so copied it.

[ReyBango]

libraries such as Prototype.js and jQuery use $ to represent getElementById()

Look at what library is being used on the page and look at the documentation for it.

Eric

Hi Eric,

Actually, the "$" is a shorthand for the jQuery namespace and is used to reference the global jQuery object.

So while many folks can use it like $( "#mydiv" ), you can also use it like jQuery( "#mydiv" ).

Rey
jQuery Project Team

[felgall]

There are 27 letters in the alphabet as far as JavaScript is concerned. a-z and $. Anywhere you can use a letter in JavaScript you can use $ as that letter. The only place where it has a special meaning beyond whatever your code defines it to mean is where it appears in a regular expression.

You can always define

function $() {alert('you are so smart');}

and then every reference to $() in your code will run that function. If you do define a function with a single letter name then that function can do whatever you want it to do. Any special meaning for such a function will be determined by which library of functions you use with your code (if any).

[Declan1991]

There's underscore too.

function _(a) {
alert(a);
}
_("Ridiculous name for a function");

[felgall]

Oops, forgot that one - JavaScript has a 28 letter alphabet.