jQuery - Utilities

Jquery provides several utilities in the $ (namespace) format. These methods are useful for performing programming tasks. Some of the utility methods are shown below.

$.trim()

$.trim() is used to remove leading and trailing spaces

$.trim( " lots of extra whitespace " );

$.Each()

$.each() is used to iterate over arrays and objects

$ . each ([ "foo" , "bar" , "baz" ], function ( idx , val ) { 
   console . log ( "element " + idx + " is " + val ); });          

 
$ . each ({ foo : "bar" , baz : "bim" }, function ( k , v ) { 
   console . log ( k + " : " + v ); });       

.each() can be called on a selection to iterate over the elements contained in the selection. .each() rather than $.each() should be used to iterate over elements in a selection.

$.InArray()

$.inArray() is used to return the index of the value in the array, or -1 if the value is not in the array.

var myArray = [ 1 , 2 , 3 , 5 ];      
 
if ( $ . inArray ( 4 , myArray ) !== - 1 ) { 
   console . log ( "found it!" ); }        

$.extend()

$.extend() is used to change the properties of the first object using the properties of subsequent objects.

var firstObject = { foo: "bar", a: "b" };
var secondObject = { foo: "baz" };
 
var newObject = $.extend( firstObject, secondObject );
 
console.log( firstObject.foo );
console.log( newObject.foo );

$.proxy()

$.proxy() is used to return a function that will always execute in the provided scope, i.e. sets the value of that parameter inside the passed function for the second argument

var myFunction = function () { 
   console . log ( this ); };    


var myObject = { 
   foo : "bar" };  

 
myFunction (); // window 
 
var myProxyFunction = $ . proxy ( myFunction , myObject );
 
myProxyFunction ();

$.browser

$.browser is used to provide information about browsers

jquery . each ( jQuery . browser , function ( i , val ) { 
   $ ( "<div>" + i + " : <span>" + val + "</span>" ) . appendTo ( document . body ); });        
   

$.Contains()

$.contains() is used to return true if the DOM element provided by the second argument is a child of the DOM element provided by the first argument, whether it is a direct child or nested more deeply.

$.contains( document.documentElement, document.body );
$.contains( document.body, document.documentElement );

$.data()

$.data() is used to provide information about the data

(new Date).getTime()

jQuery.isXMLDoc( document )
jQuery.isXMLDoc(document.body)

function test() {
   jQuery.globalEval( "var newVar = true;" )
}
test();