ASP Special Characters
All the special characters that you see when programming ASP can be a little
overwhelming at first. This lesson is aimed at providing a succinct look at
the most common special characters that occur within ASP. This lesson will
cover the following character/symbol combinations:
- &
- '
- _
- :
- .
- <%...%>
- <%=...%>
That's pretty ugly and confusing to look at, so let's get right in to the details
of each of the symbols and see what they mean.
String Concatenation: The Ampersand &
You can combine strings with the ampersand character. It
acts as a glue between one or more strings to create one large string.
See our Strings Lesson for a
more detailed look at strings and string concatenation. Below is an example of the ampersand
concatenating two strings.
ASP Code:
<%
Dim myString
myString = "One String"
myString = myString & " another string"
Response.Write(myString)
%>
Display:
One String another string
ASP Comments: The Apostrophe '
The apostrophe is used to prevent the ASP interpreter from executing the
text that follows. In ASP there is only the single line comment. Check out
our ASP Comments Lesson
for more information on comments. Below is an example of the apostrophe.
ASP Code:
<%
'This is a comment.
%>
Spanning Multiple Lines: The Underscore _
Sometimes you can't fit all your ASP code on one line because your string is too long, you
are tabbed over too far or you just want to break up the statement. With the use of the underscore you can tell the ASP interpreter
that you line of code continues to the next line. This allows you to have a single ASP statement span multiple lines.
In the following example we have such
a huge piece of code we need to span over three lines.
ASP Code:
<%
Response.Write("This is probably the longest "&_
"string to be typed out on this page and maybe "&_
"even this whole tutorial on ASP!!!")
%>
Display:
This is probably the longest string to be typed out on this page and maybe even this whole tutorial on ASP!!!
Squishing Onto a Line: The Colon :
Sometimes you want to reduce the human readability of your code because you're either mentally
disturbed or insane. The colon will help you satiate your crazy desires by
letting you put multiple lines of ASP code onto a single line. Below is an example
of how to make your code very hard to read!
ASP Code:
<%
Dim x
Dim y
Dim z
x=3 : y=25 : z=x-y : y=x*z : z=x*x-z+y : y=5*3*z*2/x
%>
Calling Methods: The Period .
ASP allows for Object Oriented Programming and these objects have methods
that can only be called by first stating the object, then placing a period and finally
calling the method by its name. The form for using the period is:
If you would like to learn more about ASP objects see our ASP Object Lesson.
Declaring ASP Code: The Percentage %
ASP files are often made up of a combination of HTML, some other stuff and ASP.
The tag that you use to stake out an area for your ASP code
does not resemble normal HTML tags. Instead it is almost like
just an opening tag that can be stretched very, very, very long. You must
use this character sequence to insert ASP code into your ASP files.
ASP Code:
<html>
<body>
<%
'My ASP code goes here.
%>
</body>
</html>
Write Shortcut: The Percentage Equal %=
The percentage equal special character sequence is a modified version
of the standard ASP code marker. This modification allows for quick access
to the Response.Write() method that is used to write information
to the web browser.
This shortcut can be used to quickly print numbers, strings, variables and anything
else you might throw at it. Below is a few examples of using this shortcut.
ASP Code:
<%=2%> <br />
<%="Hello"%> <br />
<%=Date()%>
Display:
2
Hello
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