Adobe Dreamweaver CC 2015 - Manual (Page 477)

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Templates
Last updated 6/3/2015
Template expression language
The template expression language is a small subset of JavaScript, and uses JavaScript syntax and precedence rules. Use
JavaScript operators to write an expression like this:
@@(firstName+lastName)@@
The following features and operators are supported:
• numeric literals, string literals (double-quote syntax only), Boolean literals (true or false)
• variable reference (see the list of defined variables later in this section)
• field reference (the “dot” operator)
• unary operators: +, -, ~, !
• binary operators: +, -, *, /, %, &, |, ^, &&, ||, <, <=, >, >=, ==, !=, <<, >>
• conditional operator: ?:
• parentheses: ()
The following data types are used: Boolean, IEEE 64-bpc floating point, string, and object. Dreamweaver templates
do not support the use of JavaScript “null” or “undefined” types. Nor do they allow scalar types to be implicitly
converted into an object; thus, the expression "abc".length would trigger an error, instead of yielding the value 3.
The only objects available are those defined by the expression object model. The following variables are defined:
_document Contains the document-level template data with a field for each parameter in the template.
_repeat Only defined for expressions which appear inside a repeating region. Provides built-in information about
the region
_index The numerical index (from 0) of the current entry
_numRows The total number of entries in this repeating region
_isFirst True if the current entry is the first entry in its repeating region
_isLast True if the current entry is the last entry in its repeating region
_prevRecord The _repeat object for the previous entry. It is an error to access this property for the first entry in the
region.
_nextRecord The _repeat object for the next entry. It is an error to access this property for the last entry in the
region.
_parent In a nested repeated region, this gives the _repeat object for the enclosing (outer) repeated region. It is an
error to access this property outside of a nested repeated region.During expression evaluation, all fields of the
_document object and _repeat object are implicitly available. For example, you can enter title instead of
_document.title to access the document’s title parameter.In cases where there is a field conflict, fields of the _repeat
object take precedence over fields of the _document object. Therefore, you shouldn’t need to explicitly reference
_document or _repeat except that _document might be needed inside a repeating region to reference document
parameters that are hidden by repeated region parameters.When nested repeated regions are used, only fields of the
innermost repeated regions are available implicitly. Outer regions must be explicitly referenced using _parent.
Multiple If condition in template code
You can define template expressions for if and multiple-if conditions. This example demonstrates defining a parameter
named "Dept", setting an initial value, and defining a multiple-if condition which determines which logo to display.