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Conversion of dom to jquery object

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Release： 2023-05-25 11:02:08

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DOM nodes are very important elements when using JavaScript for page development. DOM (Document Object Model) refers to parsing HTML or XML documents into a tree structure, allowing us to use JavaScript to access and manipulate any element in the document. However, sometimes we find that operating DOM nodes in details is very complicated and difficult to understand. This is why many developers prefer using jQuery. jQuery is a widely used JavaScript library, by using jQuery we can easily access and manipulate DOM nodes.

In this article, I will introduce how to use jQuery to convert DOM to jQuery objects, and how to use jQuery objects for various operations and transformations.

Conversion of DOM into jQuery objects

To convert DOM nodes into jQuery objects, we need to use jQuery's selector function. To use a selector function, we need to pass the tag name or class name or ID of the node as a parameter to the function. For example, if we have the following HTML code:

<div class="example" id="myDiv">Hello World!</div>

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We can convert it into a jQuery object using the following code:

var myDiv = $('#myDiv');

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Here, we use jQuery to convert a node into a jQuery object, using $() and then pass in '#myDiv', which is a selector that searches the HTML document for a div element with the id 'myDiv'. We can then access the element using the myDiv variable, which is now a jQuery object.

Besides that, we can also convert DOM nodes to jQuery objects by:

var myDiv = $('#myDiv')[0];

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Here, we first convert the element to jQuery using $('#myDiv') object and then use [0] to convert it back to the original DOM node. This way we can access the original JavaScript properties and DOM methods of the element.

Conversion between jQuery objects

A jQuery object can find or store one or more elements and use various methods and properties to manipulate these elements. If we need to access a single element (like in the above example), we can use [0] to access it.

However, if we want to access multiple elements, we need to use a selector that returns multiple elements. In this way, we can convert multiple elements into jQuery objects using the following code:

var divs = $('.example');

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Here we use the class selector '.example' which will search the HTML document for all elements containing that class , and returns it as a jQuery object.

In addition to using selectors to return jQuery objects for multiple elements, we can also use the following method to convert multiple elements into jQuery objects:

var listItems = $('li');
var listItem = $(listItems[0]);

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Here, we first convert all The li elements are converted to jQuery objects, then listItem[0] is used to convert the first li element back to the original DOM node.

Expansion and contraction of jQuery objects

We can also expand or contract jQuery objects by adding or removing DOM elements. We can add DOM elements to the page using the following method:

var newDiv = $('<div>');
newDiv.addClass('newDiv').text('Hello World!');
$('body').append(newDiv);

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Here, we first convert a new div element into a jQuery object using $('

') and then use addClass('newDiv' ) add a class attribute to it and add some text using text('Hello World!'). We then use append(newDiv) to add the new div element to the body element of the page.

We can also remove DOM elements from the page using the following method:

var firstListItem = $('li:first-child');
firstListItem.remove();

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Here, we first find the first li element through the selector and then use the remove() method to remove it from the page Delete the element.

Summary

Using jQuery, we can access DOM nodes very easily. We can use selector functions to convert DOM nodes into jQuery objects and manipulate them using various methods and properties.

We can also convert multiple DOM elements into jQuery objects and manipulate them using various methods and properties. We can add or remove elements to expand or shrink jQuery objects.

Using jQuery, we can more easily write maintainable and understandable JavaScript code.

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