Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Obsolete
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.
The @set
statement creates variables used with conditional compilation statements.
Syntax
@set @varname = term
Parameters
- varname
- Valid JavaScript variable name. Must be preceded by an "@" character at all times.
term
- Zero or more unary operators followed by a constant, conditional compilation variable, or parenthesized expression.
Remarks
Numeric and Boolean variables are supported for conditional compilation. Strings are not. Variables created using @set
are generally used in conditional compilation statements, but can be used anywhere in JavaScript code.
Examples of variable declarations look like this:
@set @myvar1 = 12 @set @myvar2 = (@myvar1 * 20) @set @myvar3 = @_jscript_version
The following operators are supported in parenthesized expressions:
-
! ~
-
* / %
-
+ -
-
<< >> >>>
-
< <= > >=
-
== != === !==
-
& ^ |
-
&& | |
If a variable is used before it has been defined, its value is NaN
. NaN
can be checked for using the @if
statement:
@if (@newVar != @newVar) ...
This works because NaN
is the only value not equal to itself.
Requirements
Supported in all versions of Internet Explorer, but not in Windows 8.x Store apps.