Javascript return this each

jQuery Plugin: return this vs return this.each()

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(function($) /* w w w .d e m o 2 s. co m */ $.fn.highlite = function(options) < return this.each(function() < $(this).css(< "background": "yellow" >); >); >; >)(jQuery); (function($) < $.fn.makeRed = function(options) < return this.each(function() < $(this).css(< "color": "red" >); >); >; >)(jQuery); (function($) < $.fn.mangle = function(options) < return this.each(function() < $(this).append(' - ' + $(this).data('x')); >); >; >)(jQuery); $(document).ready(function() < $('p').highlite().makeRed().mangle(); >);

html> head> meta name="viewport" content="width=device-width, initial-scale=1"> script type="text/javascript" src="https://code.jquery.com/jquery-1.7.1.js" > !-- ww w . d e mo 2 s . c o m --> body> p data-x="one">Text one p data-x="two">Text two p data-x="three">Text three p data-x="four">Text four script type='text/javascript'> (function($) < $.fn.highlite = function(options) < return this.each(function() < $(this).css(< "background": "yellow" >); >); >; >)(jQuery); (function($) < $.fn.makeRed = function(options) < return this.each(function() < $(this).css(< "color": "red" >); >); >; >)(jQuery); (function($) < $.fn.mangle = function(options) < return this.each(function() < $(this).append(' - ' + $(this).data('x')); >); >; >)(jQuery); $(document).ready(function() < $('p').highlite().makeRed().mangle(); >);   

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Jqueryplugin return this vs return this each

So, basically, function is used to apply some code to all elements contained in object ( as usually refers to a group of elements returned by a jQuery selector ) and return the reference to ( as function always returns that reference -to allow chaining calls- ) In jQuery, is an alias for the function , which is the main function that handles DOM selection.

JQueryPlugin: return this vs return this.each()

1. Your examples are flawed in that they do exactly the same thing to each element.
2. The real issue isn’t return this versus return this.each , the issue is this versus this.each .

For (1) , consider the difference between this plugin:

So you see, you need to use this.each if you need to treat the individual elements in the this set differently. You would have similar effects if your plugin had to attach element-specific data to each element: if you didn’t use each then you’d end up attaching the exact same piece of data to all of the elements inside this and that would just leave you confused about why information is bleeding all over the place.

For (2) , it doesn’t matter if you return this or return this.each(. since x.each(. ) returns x anyway.

Let me show you two «equivalent» pieces of code that could clarify your question:

With jQuery «each» function:

Without jQuery «each» function:

(function($) < $.fn.mangle = function(options) < var objs = this; for (var i=0; i; return this; >; >)(jQuery); 

So, basically, each function is used to apply some code to all elements contained in this object ( as this usually refers to a group of elements returned by a jQuery selector ) and return the reference to this ( as each function always returns that reference -to allow chaining calls- )

As a side note : The second approach ( — for loop- ) is faster (notably on old browsers) than former one ( — each function- ).

They are both exactly the same. .each() returns this , so return this.each() is EXACTLY the same as this.each(); return this;

Edit: your newest fiddle’s makeRed method doesn’t return this and is therefore not chainable.

Javascript — jQuery Plugin Return this.each and add, jQuery Plugin Return this.each and add function property to each object? Ask Question Asked 6 years, 3 months ago. Modified 6 years, 3 months …

JQueryPlugin return this vs return this.each()

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What does «return this.each()» do in jQuery?

.each returns the elements it was called on, so in this case, it is probably to maintain the ability of methods to be chained on that selector. That means that if the plugin’S method is called foo , you should be able to do

Because foo returned the result of .each which is basically $(«mySelector»).

It allows for one to call a plugin or an event on a bunch of elements and then apply that same function or event to all of them

And if, let us say, .selector contains 10 elements, all 10 elements would get whatever myPlugin does.

The reason for returning that .each statement is because .each() returns whatever it was given and it allows you to chain multiple functions and plugins together on one jQuery element.

$('.selector').myPlugin().yourPlugin(); 

It makes functions chainable

JQuery plugin structure, jQuery plugin structure. Ask Question Asked 11 years, 2 months ago. Modified 11 years, 2 months ago. Viewed 2k times 0 I’ve been working on my …

JQuery $this vs $(this) in plugin development

$this is a standard people use to cache the actual jQuery object $(this) in a variable.

You can call it what you wish, some people like to refer to it as $self.

It just helps when you are looking at the code to recognize that it is a jQuery object rather than a normal dom object.

It performs better as you only create one instance of the jQuery variable.

$ is a legitimate character for variable and function names in javascript. That might be confusing if you’re coming from PHP where $ is used to signify a variable only (took me a while to realise).

• In jQuery, $ is an alias for the function jQuery , which is the main function that handles DOM selection. $(«#header ul.menu») is the same as jQuery(«#header ul.menu») . $ is simply used for brevity.
• this is a special term in Javascript (not jQ) meaning the current element (in forms you might see this.submit() for example).
• $(this) means «call the jQuery function with Javascript’s this «.
• $this is simply a variable, since $ is a valid character. You can set $this to any value you like and it’s completely unrelated to Javascript’s this . In general I’d suggest NOT using $ for variable names to avoid confusion with the jQuery function. However, it may be useful to use $var to denote jQuery objects as opposed to normal Javascript variables.

if you are performing a number of different commands with an element wrapped in a jQuery object, then it is more performant to get the element (as a wrapped set) only once and store that in a local variable

var $this = $(this); // then use $this in your function. 

Note the use of var to locally scope $this

How to use events and event handlers inside a jquery, The event handling and triggering actually works, I just had to call the checkProgress function first: return this.each (function () < setup (obj); …

Returning true or false from a jQuery plugin

It’s returning the canvas because that’s what’s being returned from the function isBlank . return this.each(. ) returns the jQuery object isBlank was called on.

You need to set a variable before the .each , set it to true or false when needed, and then return that instead.

Note: Inside .each , return false functions like break and return true functions like continue .

(function ($) < $.fn.extend(< isBlank : function() < var ret = true; this.each(function () < var context = this.getContext('2d'), imageData = context.getImageData(0, 0, this.offsetWidth, this.offsetHeight); for (var i = 0; i < imageData.data.length; i += 4) < if (imageData.data[i+3] !== 0) < ret = false; >> >); return ret; > >); >)(jQuery); 

(function ($) < $.fn.extend(< isBlank : function() < var result = true; this.each(function () < var context = this.getContext('2d'), imageData = context.getImageData(0, 0, this.offsetWidth, this.offsetHeight); for (var i = 0; i < imageData.data.length; i += 4) < if (imageData.data[i+3] !== 0) < result = false; >> >); return result; > >); >)(jQuery); 

Basically, pull out the superfluous return statements, and return one value at the end of the function.

Your code is calling a return on this.each , which should return the object you’re calling .isBlank on. I’d remove the return on the each and see if the behavior you’re expecting comes through and declare a variable outside of the .each call that is set by the .each and returned instead, like Rocket mentioned in his answer.

JQueryPlugin: return this vs return this.each(), 3 Answers. Your examples are flawed in that they do exactly the same thing to each element. The real issue isn’t return this versus return this.each, the … Code sample$.fn.mangle = function(options) );>;Feedback

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jQuery.each()

jQuery.each( array, callback ) Returns: Object

Description: A generic iterator function, which can be used to seamlessly iterate over both objects and arrays. Arrays and array-like objects with a length property (such as a function’s arguments object) are iterated by numeric index, from 0 to length-1. Other objects are iterated via their named properties.

version added: 1.0 jQuery.each( array, callback )

version added: 1.0 jQuery.each( object, callback )

The $.each() function is not the same as $(selector).each(), which is used to iterate, exclusively, over a jQuery object. The $.each() function can be used to iterate over any collection, whether it is an object or an array. In the case of an array, the callback is passed an array index and a corresponding array value each time. (The value can also be accessed through the this keyword, but Javascript will always wrap the this value as an Object even if it is a simple string or number value.) The method returns its first argument, the object that was iterated.

$.each([ 52, 97 ], function( index, value ) 
 alert( index + ": " + value );
>);

This produces two messages:

If an object is used as the collection, the callback is passed a key-value pair each time:

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