The body VBScript and JScript are actually called low-level languages. I heard it for the first time! They can be considered as advanced languages in advanced languages. The so-called scripting language refers to a relatively simple language developed by a large software to implement complex functions. Similar to the Flash ActionScript, even some games provide scripting languages. For example, "winter night" provides a powerful scripting language, with more functions than VBScript. The script language is generally interpreted and executed. Once it is detached from its host program, it does not exist.
Specified ument. write (); window. alert () and so on. If the VBScript program is directly saved as a vbs file and runs directly in windows, its host is Windows Script Host (Windows Script Host ), in this way, you can access resources on your computer through the properties and methods of the objects provided in wsh, such as createshortcut (you can create shortcuts) and regread (you can read the registry. If you put VBScript in an ASP file, it will be executed on the Web server. At this time, its host is svchost (or IIS ), it can be used to access resources on the server, or send or obtain client data through its built-in objects such as response and request.
These script hosts are also based on the component object model so that they can also access each other. For example, create a wscript. Shell object in HTML to access the Windows Script Host:
<Script language = VBScript>
Set wshshell = wscript. Createobject ("wscript. Shell ")
Wshshell. regwrite "hkey_local_machinesoftwaremicrosoftinternet assumermainstart page", "http://www.pchome.net", "REG_SZ"
</SCRIPT>
Run the above program and your IE homepage will become pchome.
Here, we should understand that ASP is not a language, but a scripting language that allows web service programs (such as IIS) to execute and use the public Gateway Interface (CGI) A technology used to interact with a client browser (or other programs that support the HTTP protocol. The scripting language must support COM objects, because their hosts are built on the COM Object Model. Therefore, VBScript and JScript can be used as the scripting language in ASP, but not in flash!
I have to talk about CGI again. I am not very familiar with CGI, but at least I know that CGI is not a language. It defines a way for the server to interact with the client, any language can interact with the client in this way. So strictly speaking, ASP, PHP, and JSP are both CGI. However, the executable programs running on the server to process the data sent by the client are called CGI, such as C and Perl (because they were the first to implement CGI ), ASP, PHP, and so on, they use the script-based execution method so they are independent (in fact, PHP can also be implemented using CGI ). A major difference between the two is that every link of the client must start a process to execute CGI, just like running a common application, the output is not on the server's display, but on the browser on the client. The latter only needs to start a process (that is, the host Program ), all connection requests are processed in the thread of this process. In this way, the former has more resources than the latter, and the efficiency is higher than the former. In addition, CGI non-embedded programming is very troublesome and WYSIWYG, so it is used less and less now.
Now, the latest Asp.net no longer uses the scripting language and COM for processing, instead.. Net Language and.. NET Framework. The former is a fully object-oriented language with more rigorous syntax and higher efficiency. The latter completely encapsulates most of the features of the operating system and is more efficient to use than the previous loose com.
After talking so much, simply say JavaScript and JScript. Many people in the Forum asked the difference between the two. In fact, there is no difference between the two in IE. When Netscape launched JavaScript For Netscape, Microsoft then imitated JavaScript and launched JScript. Therefore, many people think that JavaScript is authentic. In fact, I tell you that these two scripting languages are not authentic. Only ecmascript is truly authentic (ECMA is the European Computer Manufacturers Association ). Both JavaScript and JScript are implemented in the ecma262 language specification. At the beginning, Microsoft and Netscape came together and jointly developed the ecma262 language to integrate JavaScript with JScript, that is to say, Javascript in Netscape and JScript in IE both comply with this standard. If you don't believe it, you can use <script language = ecmascript> to replace the original tag and it will certainly run normally. But why are there many differences between the two? In fact, this difference is not the difference between languages, but the difference between their host programs. IE and Netscape do not have the same attributes and methods for their built-in objects, thus creating a different programming inconsistency between the two. If IE has the window. navigate () method, Netscape does not.
The above are some of the points I have made through web development over the past few years. I only hope that beginners can understand some basic definitions and avoid detours. The level is accumulated based on actual experience, rather than several certificates. The certificate applicant's low quality does not mean that Microsoft certificates have low gold content. How many people do not rely on le?
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Postscript (not written by the original author, but my own idea)-* _ *-beginners may encounter many concepts and often do not understand them clearly, however, the online articles are rarely clear to beginners. For example, what exactly does JRE and JVM do? Why is there a JVM and JRE. I think the introductory articles are generally read by people who understand them. That is the case. People who do not understand them still do not understand :(. This article makes the concept clearer. At least I have clearly explained what the author understands. Unlike some "Daniel", I am not quite clear about it. I am still confused about it.
