@set Statement (JavaScript)

varname

Required. Valid JavaScript variable name. Must be preceded by an "@" character at all times.

term

Required. Zero or more unary operators followed by a constant, conditional compilation variable, or parenthesized expression.

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.

Supported in all versions of Internet Explorer, but not in Windows Store apps.

Reference

Concepts