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Declares a variable and binds a value to that variable.
[select = "expression2"]
[expr = "expression3"]>
name attribute is required, and it must be a string. The value of the
name attribute is a qualified name.
The value that you bind to a variable can be an object of any of the types that are returned by expressions. You can specify the value of the variable in several ways:
- Specify the
select attribute. The value of the
select attribute must be an expression. The XSLT processor evaluates the expression, and the result is the value of the variable. If you specify the
select attribute, you must not specify any contents for the
xsl:variable instruction. In other words, do not specify template_body.
- Specify the
expr attribute. It is interpreted as an attribute value template. It allows computation of the value expression.
expr attribute of the
xsl:variable instruction is an extension of the XSLT standard. If you want to use an XSLT processor other than the Stylus Studio processor, you cannot specify the
expr attribute in your stylesheet.
- Specify template_body. The XSLT processor instantiates this template to obtain the value of the variable. If you specify template_body, you must not specify the
- Specify none of the above. In this case, the value of the variable is an empty string.
The difference between the
xsl:variable instructions is that
xsl:param defines a default value while
xsl:variable defines a fixed value.
For any use of the
xsl:variable element, there is a region of the stylesheet tree within which the binding is visible. This region includes the siblings that follow the
xsl:variable instruction together with their descendants. Within this region, any binding of the variable that is visible on the
xsl:variable element itself is hidden. Thus, only the innermost binding of a variable is visible. The set of variable bindings in scope for an expression consists of those bindings that are visible at the point in the stylesheet where the expression occurs.
xsl:variable instruction can be a top-level element. If it is, it declares a global variable that is visible to the entire stylesheet. When the XSLT processor evaluates the
expr attribute in a top-level
xsl:variable instruction, the current node is the root node of the document. The
xsl:variable instruction is also allowed anywhere in a template that an XSLT instruction is allowed.