What kind of JavaScript is this?

Question

I have an application that has this format scattered around but I dont know what kind it is. It's not jQuery, so what is it?

$('some_edit').style.display  = "block";
$('some_views').style.display = "none";

I get this in firebug and I know the element is present:

$("some_edit").style is undefined

Answer 1

它可能是很多东西 - 检查源代码（或使用Firebug）并查看正在加载的JS库。

Answer 2

A lot of people have defined the '$' symbol as a substitute for document.getElementById().

Basically:

function $(id) { return document.getElementById(id); }
$("ElementID").innerHTML = "Text"; //Usage

A more proper, "namespace" example:

var DOM = { // creating the namespace "DOM"
    $: (function() {
        if(document.getElementById)
            return function(id){ return document.getElementById(id); }
        else if(document.all)
            return function(id) { return document.all[id]; }
        else
            return function(id) { /* I don't even want to get into document.layers */ }
    })()
};

// Later in the code:
{
    function ExampleFunction() {
        // ...
        DOM.$("ElementID").style.backgroundColor = "#96d0a0"; // a nice minty green color
        // ...
    }
}

I have used a self-invocation pattern ( function(){ ... }() ) in this example.

Answer 3

at first i thought the jquery selector would likely have been $("#some_edit") and then .css() . so I would have said, prototype or mootools or a home brew $.

you can certainly discount both mootools and prototype , because if the selector returns an object, then the style property will be available (ignoring best practices in both frameworks on setting styles).

this leaves, the site uses homebrew $ assignment or jquery, which is not being used correctly.

actually, $("foo").style.blah in jquery will produce this very exception (even if the selector was good) - here is jsfiddle to the rescue

case point jquery (triggers): http://www.jsfiddle.net/dimitar/vmsZn/

case point prototype (works): http://www.jsfiddle.net/dimitar/vmsZn/1/

case point mootools (works): http://www.jsfiddle.net/dimitar/vmsZn/2/

Answer 4

It is setting the display style for the two page elements - the display property specifies the type of box an element should generate.

block = The element will generate a block box (a line break before and after the element) none = The element will generate no box at all

Answer 5

Put a [0] in front of $('some_views') to return the Native DOM Element.

$('some_views')[0].style.display = "none";

or $('some_views').get(0).style.display = "none";

or $('some_views').css('display', 'none') to iterate through the collection of DOM elements.

Answer 6

It's JQuery -- uses $ as its key variable.

Added:

Could also be mootools. Also uses $

Added:

'some_edit' would be the id of an element.

ps. I agree $ could be anything. Odds are though that it is JQuery or Mootools. "When you hear hoof beats, think horses, not zebras."