Introduction to ASP Introductory learning experience

Request.Form < "form element name" >


request.querystring "Address bar parameter name" "


formatdatetime Function: Format date or time


ABS (number) function: To find absolute value


now () feature: Get current time Note: Functions that do not require parameters


FormatDateTime (date ", NamedFormat") Feature: Format time note "Functions that require one or several parameters"


sin (number) function: Take the sin value


UCase (String) feature: Transformations such as "he can convert uppercase and lowercase" to a function that requires one or several parameters


If an argument is enclosed in parentheses, it must be written without a date. If the function has multiple arguments each argument is separated by the ","


can be written in English when using a constant as a parameter, or it can be written directly into a value.





function: is a module of the program code, as long as the definition, we can call in other programs that use them.


Usually a function has one or more parameters, a predefined program for a series of operations, and the resulting result is returned with the function name. For the program code that needs to be written over and over again, just call them using the name of the function wherever you need them.





1. Methods for defining functions: <%


define function keyword function name ([parameter})


statement block
to implement function function

function name = value that needs to be returned (function run result)


End Function


%>


Note: Define before the function call! 》





2. Method to define a subroutine: Sub subroutine name ([parameters])


statement block
to implement subroutine function

End Sub


This shows that the definition function (2) is a function that has a return value, and a subroutine is a function that has no return value.


has keywords in front of words such as (call): subroutine parameters must be enclosed in parentheses and if you add parameters directly with subroutine names you do not need to enclose the extension number


Focus: Global variables can also be used in subroutines, and local variables with the same name in subroutines may invalidate global variables.


when we call a function value that does not need to return a value, it is also possible to use the called statement.


functions and subroutines can both use global variables directly, and you can change the values of global variables within a function or subroutine.


3. Parameter transmission mode: The way of passing value and the way of ByVal The specified parameter is passed as a value-passing method.




When
calls a function, it passes the value of the argument to the formal parameter, which is, in fact, not the default in the Vbsscript language, which passes the address of the argument to the formal parameter.

The
method is to give the formal parameter the lattice number of the argument, so that when the parameter changes the value, the variable value in the lattice number is changed.

The way the
function parameter is passed is by default the address method.

The
method is to copy the value of the actual parameter to the formal parameter, so that no matter how we change the parameters in the function or subroutine, it does not affect the value of the argument.


if we want to pass an array as a parameter, we can take the array name directly as an argument.

The
ContentType property specifies the HTTP output content type response.contenttype= content Type


binarywrite function: Output The specified information without any conversion, and it mainly outputs non character information.


syntax: response.binarywrite binary Data


Redirect method: Its role is to jump the Web page, it and clear and flush method, the buffer property is dependent on, that is, if you want to use the Redirect method in the Web page, you must set the Buffer property to ture usage: respons E.redirect Web site

The
buffer property is used to set whether the page is cached after the output. The setting of the buffer property is best in the first line of the ASP file.


session and cookies are the most common point is that they can be used to save the user's data or tracking the user's biggest difference is that the session is stored in the "server" and cookies stored in the "client" machine.


session is more secure than cookies because session is stored on the server and cookies are stored on the client, it is easy to change the client information, but it is difficult to change the server information, so the session is safe.


When a session variable is established, it can be used on other pages of the site if there is no timeout or human deletion.


Select field Name table, [Top return record bar count]; from datasheet sequence; [Where condition expression]


[Order By Sort Field table [Asc/desc]] Note: ("[]") the statements in parentheses are optional and the meaning of the parentheses in the function syntax select * Form info Query Info table all the records meaning Thought as: (select all fields from info table)