An explanation of the difference between JS and JSP

Recently, many students are struggling with the similarity between noun abbreviations, so I will also write an article to talk about the difference between JS and JSP.

SUN first developed SERVLET, which has relatively powerful functions and advanced system design. However, it still uses the old CGI method to output HTML statements, which is output sentence by sentence. Therefore, Writing and modifying HTML is very inconvenient. Later, SUN launched a mosaic JSP similar to ASP, which embedded JSP TAG into HTML statements. This greatly simplified and facilitated the design and modification of web pages.

The full name of JSP is Java Server Pages. It is basically a simplified Servlet design. It implements the java expansion in Html syntax (with < ;%, %> form). JSP, like Servlet, is executed on the server side. Usually what is returned to the client is an HTML text, so the client can browse it as long as it has a browser. When the web server encounters a request to access a JSP web page, it first executes the program segment, and then returns the execution result to the client together with the HTML code in the JSP file. The inserted Java program segments can operate databases, redirect web pages, etc. to achieve the functions required to create dynamic web pages.

#JSP page consists of HTML code and Java code embedded in it. The server processes these Java codes after the page is requested by the client, and then returns the generated HTML page to the client's browser. Java Servlet is the technical foundation of JSP, and the development of large-scale Web applications requires the cooperation of Java Servlet and JSP to complete. JSP has all the characteristics of Java technology that are simple and easy to use, completely object-oriented, platform-independent, safe and reliable, and mainly oriented to the Internet.

jsp must be translated first. Note that it must be translated into a servlet before it can be executed:
For example, test.jsp should become test_jsp.java and then compiled into test_jsp.class
And test_jsp. Java itself is a servlet.
So jsp is just a variant of servlet, which is convenient for writing html content.
Servlet is the foundation, everything jsp can do, servlet can do it all.

The running mechanism of servlet is similar to that of Applet, except that it runs on the server side. A servlet is a subclass of the HttpServlet class in the javax.servlet package. The server that supports servlet completes the object of this subclass, that is, the initialization of the servlet.

##Extended reading 0: The process of converting jsp into servlet:

##http://www.w3cschool.cc/jsp/jsp-architecture.html

Extended reading 1: servlet version of Helloworld (needs tomcat installation, I usually use XAMPP integrated tomcat)

##http://blog.163.com/adoom_2010/blog/static/1820326362011710102719527/

Extended reading 2: The role and calling sequence of each part in the servlet program

http://wenku.baidu.com/link?url=U2B6Gx_C1X702ppIFJdXR23MyY85lZzJeneIDZSFCuA3bZ-ynwDFx9oYm4pNcpa4ZjmlUPnkrtwkHg0skxdo3mqOY-IAvXzzYqaCOc7DVmW

## JS is the abbreviation of Java Script, an object-based client-side scripting language. The main purpose is to solve the speed problems left by server side languages, such as Perl, and provide customers with a smoother browsing effect. JS can be directly embedded into HTML code for parsing and execution. It is very simple and easy to learn and can produce many dynamic effects.

Extended reading: http://www.w3school.com.cn/js/

Simply put - JS is executed on the client side and requires the browser to support Javascript. JSP is executed on the server side and requires a server program that supports Servlets to be deployed on the server. JS code can be downloaded directly from the server and is visible to the outside world, while jsp (and translated servlet) code is invisible to the outside world.

Compared with JavaScript: Although JavaScript can dynamically generate HTML on the client, it is difficult to interact with the server and therefore cannot provide complex services, such as access Database and image processing, etc. JSP is implemented in HTML using <%%>. JS is implemented in html using <Script></Script>

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