An Active Server Pages Tutorial, Part 2 Oklahoma

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Originally published at Internet.com

Review Part 1

Session 6

Boolean Functions in VBScript and Their Application in ASP

<% Dim x(10) Response.write(IsArray(x)) Returns true Dim x document.write(IsArray(x)) Returns false %> IsDate

Determines whether a variable is a valid date or not. Dim x
x = "12/10/00"
document.write(IsDate(x))
Returns true
x = "555"
document.write(IsDate(x))
Returns false

<%
Dim x
x = "12/10/00"
Response.write(IsDate(x))
Returns true
x = "555"
document.write(IsDate(x))
Returns false
%>

IsEmpty Determines whether a variable has been initialized. Variables are empty when you declare them or explicitly set them to empty <%
Dim x
document.write(IsEmpty(x)) Returns true
x = "12/15/00"
document.write(IsEmpty(x)) Returns false
x = Empty
document.write(IsEmpty(x)) Returns true
%>

<%
Dim x
Response.write(IsEmpty(x)) Returns true
x = "12/15/00"
Response.write(IsEmpty(x)) Returns false
x = Empty
Response.write(IsEmpty(x)) Returns true
%>

IsNull

Determines whether a variable is null or not Dim x
document.write(IsNull(x)) Returns false
x = Empty
document.write(IsNull(x)) Returns false
x = Null
document.write(IsNull(x)) Returns true <%
Dim x
Response.write(IsNull(x)) Returns false
x = Empty
Response.write(IsNull(x)) Returns false
x = Null
Response.write(IsNull(x)) Returns true
%>

IsNumeric Returns true if the variable can be evaluated as a number

Dim x, y
x = 20
document.write(IsNumeric(x)) Returns true
y= "Hello"
document.write(IsNumeric(x)) Returns false <%
Dim x, y
x = 20
Response.write(IsNumeric(x)) Returns true
y= "Hello"
Response.write(IsNumeric(x)) Returns false
%>