not

The not function evaluates a boolean expression and returns the opposite value.

Syntax

not( expression )

Parameters

expression

The expression is evaluated exactly as if it were passed as an argument to the boolean() function.

Return value

True for an expression that evaluates to false; false for an expression that evaluates to true.

Description

• This function should behave similarly to the boolean() function except that it returns the opposite value.

• You can test if an element doesn't have some attribute.

  xml

  <xsl:for-each match="//a[not(@name and @name = 'badname')]">
   <!-- iterates over any <a> element in the document, that
   either has no 'name' attribute at all, or it has one,
   but its value is not "badname". -->
  </xsl:template>
  

Specifications

XPath 1.0 4.3

Gecko support

Supported.