jQuery exercises [1] Preparations for learning jquery_jquery

Using jQuery to write JavaScript scripts is like using Delphi to write Windows programs. It is not more powerful, but easier to use.

I plan to comprehensively browse and test the syntax of jQuery first, and gain insight into its logic and ideas; finally try Using jQuery in Delphi is probably much more convenient than using MSHTML.pas.

Official site: http://jquery.com/
Chinese document: http ://jquery-api-zh-cn.googlecode.com/
Download address: http://docs.jquery.com/Downloading_jQuery

jQuery library is A js file has versions with different specifications:

To view the source code, you should use: standard version (such as: jquery-1.4.2.js)
In actual applications, you should use: min version (such as: jquery- 1.4.2.min.js);
You can use the vsdoc version with code prompts when editing in VS, but the latest version of vsdoc that can be found is 1.4.1, which is also acceptable.

PS: The following running code is added with jquery. After running, refresh it and you can see the effect.

should be called in the page before use; test page:

...
[Ctrl A Select all Note:

If you need to introduce external Js, you need to refresh to execute it
]

The jQuery code should be written in Where? This is no different from ordinary JavaScript, such as the following code: ...

[Ctrl A Select all Note:
If you need to introduce external Js, you need to refresh to execute
]

Use jQuery, above The code can be changed to:
...

[Ctrl A Select all Note:

If you need to introduce external Js, you need to refresh to execute ] Abbreviation:
...

[Ctrl A Select all Note:

If you need to introduce external Js, you need to refresh to execute ] $(document) is jQuery object, similar but different from window.document; jQuery has its own set of systems (objects, methods, events, etc.). $(document).ready() is similar but different from (earlier than) window .onload(), and the former can be used repeatedly:
...

[Ctrl A select all Note: <script> //完整的写法 jQuery(document).ready(function() { alert("Hello"); }); //jQuery 可简写为 $ $(document).ready(function() { alert("Hello"); }); //$(document) 可以简写为 $() $().ready(function() { alert("Hello"); }); //$(document).ready() 也可以简写为 $() $(function() { alert("Hello"); }); </script>If you need to introduce external Js, you need to refresh to execute ]<script> $(function() { alert("Hello jQuery 1") }); window.onload = function() { alert("Hello JavaScript 1") }; //这会被覆盖 window.onload = function() { alert("Hello JavaScript 2") }; $(function() { alert("Hello jQuery 2") }); </script>
window.onload() 发生在页面载入完成时,
$(document).ready() 发生在页面主体框架载入完成时(或许某个图片还没下载完);
当需要这个时机时, 我更喜欢把代码放在页尾:

<script src="http://code.jquery.com/jquery-1.4.2.min.js"></script> <script> window.onload = function() { alert("Hello 4") }; $(function() { alert("Hello 3") }); </script> 页面内容 <script> alert("Hello 1"); </script> <script> function fun() { alert("Hello 2") }; fun(); </script>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]

用什么工具呢? 听说有很多, 我觉得 VS 就不错, 还有代码提示, 就是太慢了, 不如自己写一个:


JavaScriptTest2.rar