Utilities

Jquery provides serveral utilities in the formate of $(name space). These methods are helpful to complete the programming tasks.a few of the utility methods are as show below.

$.trim()

$.trim() is used to Removes leading and trailing whitespace

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

$.each()

$.each() is used to Iterates 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(), not $.each(), should be used for iterating over elements in a selection.

$.inArray()

$.inArray() is used to Returns a value’s index in an 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 Changes 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 Returns a function that will always run in the provided scope — that is, sets the meaning of this inside the passed function to the second argument

varmyFunction=function(){
   console.log(this);};var myObject ={
   foo:"bar"};myFunction();// windowvar myProxyFunction = $.proxy( myFunction, myObject );myProxyFunction();

$.browser

$.browser is used to give the information about browsers

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

$.contains()

$.contains() is used to returns true if the DOM element provided by the second argument is a descendant 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 give the information about data

<html lang = "en"><head><title>jQuery.data demo</title><script src = "https://code.jquery.com/jquery-1.10.2.js"></script></head><body><div>
     The values stored were &lt;span&gt;&lt;/span&gt;
        and &lt;span&gt;&lt;/span&gt;&lt;/div&gt;&lt;script&gt;
     var div = $( "div" )[ 0 ];
     jQuery.data( div, "test", {
        first: 25,
        last: "tutorials"
     });
     $( "span:first" ).text( jQuery.data( div, "test" ).first );
     $( "span:last" ).text( jQuery.data( div, "test" ).last );
  &lt;/script&gt;&lt;/body&gt;&lt;/html&gt;</pre>

An output would be as follows

The values stored were 25 and tutorials

$.fn.extend()

$.fn.extend() is used to extends the jQuery prototype

<html lang = "en"><head><script src = "https://code.jquery.com/jquery-1.10.2.js"></script></head><body><label><input type = "checkbox" name = "android"> 
     Android&lt;/label&gt;&lt;label&gt;&lt;input type = "checkbox" name = "ios"&gt; IOS&lt;/label&gt;&lt;script&gt;
     jQuery.fn.extend({
        check: function() {
           return this.each(function() {
              this.checked = true;
           });
        },
        uncheck: function() {
           return this.each(function() {
              this.checked = false;
           });
        }
     });
     // Use the newly created .check() method
     $( "input[type = 'checkbox']" ).check();
  &lt;/script&gt;&lt;/body&gt;&lt;/html&gt;</pre>

It provides the output as shown below −https://www.tutorialspoint.com/jquery/src/fn.utilities.htm

$.isWindow()

$.isWindow() is used to recognise the window

<!doctype html><html lang = "en"><head><meta charset = "utf-8"><title>jQuery.isWindow demo</title><script src = "https://code.jquery.com/jquery-1.10.2.js"></script></head><body>
  Is 'window' a window? &lt;b&gt;&lt;/b&gt;&lt;script&gt;
     $( "b" ).append( "" + $.isWindow( window ) );
  &lt;/script&gt;&lt;/body&gt;&lt;/html&gt;</pre>

It provides the output as shown below −https://www.tutorialspoint.com/jquery/src/iswindow.htm

$.now()

It returns a number which is representing the current time

(new Date).getTime()

$.isXMLDoc()

$.isXMLDoc() checks whether a file is an xml or not

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

$.globalEval()

$.globalEval() is used to execute the javascript globally

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

$.dequeue()

$.dequeue() is used to execute the next function in the queue

<!doctype html><html lang = "en"><head><meta charset = "utf-8"><title>jQuery.dequeue demo</title><style>
     div {
        margin: 3px;
        width: 50px;
        position: absolute;
        height: 50px;
        left: 10px;
        top: 30px;
        background-color: green;
        border-radius: 50px;
     }
     div.red {
        background-color: blue;
     }
  &lt;/style&gt;&lt;script src = "https://code.jquery.com/jquery-1.10.2.js"&gt;&lt;/script&gt;&lt;/head&gt;&lt;body&gt;&lt;button&gt;Start&lt;/button&gt;&lt;div&gt;&lt;/div&gt;&lt;script&gt;
     $( "button" ).click(function() {
        $( "div" )
        .animate({ left: '+ = 400px' }, 2000 )
        .animate({ top: '0px' }, 600 )
			
        .queue(function() {
           $( this ).toggleClass( "red" );
           $.dequeue( this );
        })
			
        .animate({ left:'10px', top:'30px' }, 700 );
     });
  &lt;/script&gt;&lt;/body&gt;&lt;/html&gt;</pre>

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