What Is The Difference Between A Dollar Sign And A Dollar Sign Followed By A Period In Jquery?
Solution 1:
$
is a reference (or synonym, if you want an analogy) to the global jQuery
object. $.<method>
calls a static method of the jQuery
object, where $(<selector>)
creates a new instance of the jQuery
object.
Solution 2:
In the context of jQuery, $
refers to the global jQuery
object.
$.
by itself is invalid JavaScript. As $
is an object, methods on this object are called like on any other object: $.methodname()
.
Maybe it becomes clearer by substituting $
with jQuery
: jQuery.methodname()
.
Solution 3:
I presume you are asking about the syntactic difference between $('#selector');
and $.parseJSON(str);
.
The former is an invocation of a function called $
and the latter invokes it's method called parseJSON
. Yup, functions can have methods - it is possible because Javascript functions are also objects. Figuratively speaking:
<scripttype="text/javascript">function$(str) {
alert(str);
}
$.parseJSON = function () {
alert('Parsing JSON');
}
$('Hi');
$.parseJSON('{}');
</script>
Solution 4:
From http://en.wikipedia.org/wiki/JQuery:
the $ function, which is a factory method for the jQuery object. These functions, often called commands, are chainable; they each return a jQuery object
$.-prefixed functions. These are utility functions which do not work on the jQuery object per se.
Typically, access to and manipulation of multiple DOM nodes begins with the $ function being called with a CSS selector string, which results in a jQuery object referencing matching elements in the HTML page. This node set can be manipulated by calling instance methods on the jQuery object, or on the nodes themselves. For example:
$("div.test").add("p.quote").addClass("blue").slideDown("slow");
This line finds the union of all div tags with class attribute test and all p tags with CSS class attribute quote, adds the class attribute blue to each matched element, and then slides them down with an animation. The $ and add functions affect the matched set, while the addClass and slideDown affect the referenced nodes.
The methods prefixed with $. are convenience methods or affect global properties and behaviour. For example, the following is an example of the map function called each in jQuery:
$.each([1,2,3], function(){ document.write(this + 1); });
This writes the number 234 to the document.
Solution 5:
$
- dollar sign is also same as Jquery usage. But I preferred to use dollar sign because I like the way dollar sign is.
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