The difference between writing jquery and directly writing JS (from a steamed bun blog)

jquery can greatly simplify the writing of JavaScript programs, I recently took the time to understand the jquery, I started the process of notes and share with you, I hope to be helpful to everyone.

To use jquery, first add a reference to the jquery library in front of the HTML code, such as:

<script language= "javascript" src= "/js/jquery.min.js" ></script>

Library files can be placed on-premises, or directly use the CDN of a well-known company, the advantage is that these large companies are more popular CDN, users visit your site before it is likely to visit other sites have been cached in the browser, so it can speed up the opening of the site. Another benefit is obvious, saving the traffic bandwidth of the website.

Provided by Google

Http://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js

The official jquery

Http://code.jquery.com/jquery-1.6.min.js

I've got my own subdomain, and I'm actually jumping to Google's Cdn.

Http://cdn.akcms.com/js/jquery.js

The specific wording of the jquery code and the native JavaScript notation differ from the following when performing common operations:

1 Positioning Elements
Js
document.getElementById ("abc")

Jquery
$ ("#abc") Location by ID
$ (". ABC") through class positioning
$ ("div") positioned by tag

It is important to note that the result of JS return is this element, jquery returns the result is a JS object. The following example assumes that element ABC has been positioned.

2 Changing the contents of an element
Js
abc.innerhtml = "Test";
Jquery
abc.html ("test");

3 Show hidden elements
Js
Abc.style.display = "None";
Abc.style.display = "block";

Jquery
Abc.hide ();
Abc.show ();

Abc.toggle ();
Toggle between show and hide (2012.4.21 update)

4 getting Focus

JS and jquery are the same, both Abc.focus ();

5 Assigning a value to a form
Js
Abc.value = "Test";
Jquery
Abc.val ("test");

6 Getting the value of a form
Js
alert (Abc.value);
Jquery
Alert (Abc.val ());

7 setting elements are not available
Js
Abc.disabled = true;
Jquery
Abc.attr ("Disabled", true);

8 Modifying element styles
Js
Abc.style.fontsize=size;
Jquery
Abc.css (' font-size ', 20);

Js
Abc.classname= "Test";
Jquery
Abc.removeclass ();
Abc.addclass ("test");

9 Ajax
Js
Create objects themselves, handle browser compatibility and other messy problems, omit the table
Jquery
$.get ("abc.php?a=1&b=2", recall);
Postvalue = "a=b&c=d&abc=123";
$.post ("abc.php", Postvalue, Recall);

function recall (Result) {
alert (result);
If the JSON is returned, the following processing
result = eval (' (' + result + ') ');
alert (result);
}

10 Determine if check box is selected
Jquery
if (abc.attr ("checked") = = "Checked")
Note: Online said. attr ("checked") = = true is not actually used, the above test can be used