Basic Scripting in VBScript  VBScript must enclosed by  No HTML code is allowed inside a VBScript code block  Nested scripting block is not allowed  Spaces within a scripting block are ignored  A VBScript code can be placed in any where in an ASP  VB style comments are permitted

VBScript Variables  VBScript variables follows the same naming rules as other programming language (e.g, C++)  Begin with an alphabetic character  Case insensitive  Variables are not typed (variants)  The type of a variable depends on its value  All types are treated the same myVariable = myVariable = “Hello World” myVariable = True myVariable = False

Types Supported inVBScript  Numeric types Integer, byte, long, single, double  Strings, Date, Boolean (true or false)  TypeName() function  Returns the type name of a variant myVariable = “Hello World” IF typeName(myVariable) = “String” THEN …  Type constants  Compare the type of a variable myVariable = “Hello World” IF myVariable = VbString THEN …

Variable Scopes  Local variables  Variables declared inside a function or procedure  Global variables  Variables declared outside of functions/procedures  The scope of a global variable is within the page Dim var1, var2 var1 = 123 ‘global variable Sub myProcedure() var1 = “Hello World” ‘local variable

Arrays  Array size must been declared  Redim can be used to change array size  Array index starts from 0 Dim arrayA(29) ‘an array with 30 elements FOR i = 0 TO 29 arrayA(i) = “testing” NEXT  VBScript supports multi-dimension arrays Dim arrayB(4, 4) ‘an two dimensional array arrayB(0, 0) = “hello”

ASP Object Model  Standard objects:  Application object - application session management  Request object - retrieve client data  Response object - send output to browsers  Session object - client session management  Standard components:  Ad Rotator - automatic rotating AD’s  Page Counter component  Database access component  File access component

Request Object

QueryString Object  Retrieve data submitted through  URL parameters  Form fields submitted using the “GET” method  QueryString object usage  request.queryString(“classID”) returns “dt2663”  request.queryString returns a collection of namevalue pairs <% for each qsName in request.queryString response.write(qsName) next %>

QueryString Element Count Request.queryString(a-name).Count  Returns the number of values of a name itemNo=JK100,JK231,JK681 request.queryString(itemNo).count ---> 3  Used for multi-valued name value pairs  Multiple checkboxes  Multiple selected items in a dropdown list  Any form fields with multiple values

QueryString Example <% for each qsName in request.queryString valNum = request.queryString(qsName).count response.write(qsName & "=") if valNum = 1 then val = request.queryString(qsName) response.write(val) else for i = 1 to valNum val = request.queryString(qsName)(i) response.write(val & ",") next end if response.write(" ") next %>

Form Object  Allows to access form submission data  The methods are similar to that of queryString <% for each formField in request.form valNum = request. form(formField).count response.write(formField & "=") if valNum = 1 then val = request. form(formField) response.write(val) else for i = 1 to valNum val = request. form(formField)(i) response.write(val & ",") next end if response.write(" ") Next %>

Response Object  Generate HTML output for web browsers  Response.write() is used in a scripting block to produce output response.write(request.queryString(qsName))  is a short cut for request.write() function <% myVariable = “Hello” youVariable = “World” response.write(myVariable & “ “ & youVariable) %>

Response Object Properties/Methods  Response.buffer  Set it on (true) or off (false)  response.flush() - sends bufferred output & continue script processing  response.clear() - erase bufferred contents  response.end() - sends buffered output & stop script processing  Response.expires = minutes When cached pages should expire in web browsers  Response.expiresAbsoluate = date/time When cached pages expire in web browsers  Response.redirection = URL Branch off to the specified web page

Summary  ASP Architecture  ASP object model  Basic VBScript scripting techniques  VBScript control structures  Request object  Response object