As far as server-side processing is concerned, ASP is a relatively new technology for generating dynamic web pages. What does a dynamic page mean? For the time being, we will not consider the progress in client-related functions, nor will we discuss client scripts, Java Applets, dynamic HTML or ActiveX controls. The dynamic page here refers specifically to the page generated by the server in response to client requests, and the page generated each time may be different depending on the situation.
To give a simple example, create a page that contains only the current date and time. A different value will be displayed each time the page is requested, because the date and time depend on the server's clock, or on a resource that provides the date and time (such as a standalone server or from a standard clock on the internet). Of course, dynamic pages are actually much more complicated than this, perhaps displaying the current value of the database record or a summary of the mail message waiting on the mail server. It is important that the server not only reads an unformatted HTML page, or text files on disk and sends them to the client, but also, some work must be done to create the page.
Internet server application programming interface
Traditional technology uses an interface with a web server, which is called the Internet Server Application Programming Interface (ISAPI).
ISAPI can be used to execute other applications that read client requests values and create web server responses through C-style stdin and stdout data stream functions. All ISAPI applications have to do is write the text and HTML of the corresponding result page and output it to the web server through the stdout function. In fact, what really does inside ASP DLL is more object-oriented.
IIS has run ISAPI's application and script interpreter since the beginning. It provides a special interpreter dynamic link library that gives another way to access the server's requests and responses, although subject to certain restrictions. It is implemented by including instructions on the server side, and the reason is said so is because they are executed on the server and the results are contained in the response delivered to the client. This feature is implemented in IIS through a dynamic link library called ssinc.dll. By default, IIS maps any page with file extensions of .shtml, .shtml, or .stm to this dynamic link library. Open the Properties dialog box of the default Web site and click the Configuration button in the Application Setting to see this mapping.
In this way, pages with these mapped file extensions will be sent to ssinc.dll for processing. Therefore, all server-sides in the execution page contain statements, and the result (if any) is inserted into the server's response, that is, into the page received by the client.
Because these files are mapped to the ssinc.dll file instead of to the ASP dynamic link library (asp.dll), all ASP code in these pages will be ignored and sent to the client in its original state, and the client will You can see these scripts. However, there is a way to avoid this in ASP 3.0, and later we will look at this method when discussing the Execute and Transfer methods of Server objects.