What does $ stand for in JavaScript?For example, I write a mouseover event:
$(document).ready(function(){
$("p").mouseover(function(){
$("p").css("background-color","#333");
});
});
$ is just an ordinary character, because of the wide application of jquery, $ is used as the identifier of jquery.
<link rel= "stylesheet" type= "Text/css" href= "/html/csstest1.css" >
<body>
<p> me, too! </p>
</body>
The rel= "stylesheet" attribute value is used to accommodate different browsers and add properties
jquery is a fast, concise JavaScript framework that is a good JavaScript code base (or JavaScript framework) after prototype.。 The purpose of jquery design is "write Less,do more", which advocates writing less code and doing more things. It encapsulates the functionality code common to JavaScript, providing a simple JavaScript design pattern that optimizes HTML document manipulation, event handling, animation design, and Ajax interaction. The core features of jquery can be summed up with a unique chain syntax and a short and clear multi-function interface, a highly efficient and flexible CSS selector, and the ability to extend the CSS selector, with convenient plug-in extension mechanisms and rich plugins. jquery is compatible with a variety of mainstream browsers such as IE 6.0+, FF 1.5+, Safari 2.0+, Opera 9.0+, and more.
What is an El expression? and easy-to-use methods
EL (Expression Language) is designed to make jsps easier to write. The expression language is inspired by the ECMAScript and XPath expression languages, which provide a way to simplify expressions in the JSP, simplifying the code for the JSP.
1. Grammatical structure
${expression}
2, [] and. Operators
EL provides "." and "[]" operators to access data.
"[]" must be used when the name of the property to be accessed contains special characters, such as. Or-such as symbols that are not letters or numbers. For example:
${user. My-name} should be changed to ${user["My-name"}
if you want to dynamically fetch values, you can do it with "[]" and "." cannot be dynamically evaluated. For example:
${sessionscope.user[data]} in data is a variable
3. Variables
the EL Access variable data method is simple, for example: ${username}. It means to take out a variable whose name is username in a range.
because we do not specify a range of username, it will be searched sequentially from page, Request, Session, application range.
if the way to find username, directly back, no longer continue to find, but if all the scope is not found, the return "".
Genus
What does $ stand for in JavaScript? What language is/jquery? Rel= "stylesheet" property in/html when introducing CSS with the link tag? What is an/el expression?
