Asc, AscB, AscW Functions
Data Type: String
Any expression that evaluates to a string.
An integer that represents the character code of the first character of the string.
Returns the ANSI (in the case of Asc) or
Unicode (in the case of AscW
Rules at a Glance
The string expression passed to the function must contain at least one character, or a runtime error (either “Invalid use of Null” or “Invalid procedure call or argument”) is generated.
Only the first character of the string is evaluated by Asc, AscB, and AscW.
Use the AscW function to return the Unicode character of the first character of a string.
Use the AscB function to return the first byte of a string containing byte data.
<% Dim sChars Dim iCharCode sChars = Request.Form("chars") If Len(sChars) > 0 Then CharCode = Asc(sChars) If iCharCode >= 97 And iCharCode <= 122 Then Response.Write "The first character must be uppercase" Else Response.Write iCharCode End If End If %>
Programming Tips and Gotchas
Always check that the string you are passing to the function contains at least one character using the Len function, as the following example shows:
If Len(sMyString) > 0 Then iCharCode = Asc(sMyString) Else Response.Write "Cannot process a zero-length string" ...
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