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- The whole expression needs to be surrounded by curly brackets, and the first character within the curly brackets must the the equals sign ‘=’, i.e.
{= ..expression ....} - The reference to the data model field is made with the ${field} syntax. The '/' is not required, so both of the following options will work: used to indicate that the field you want to bind to is at the root node of your data model (and not, for example, in a table).
{$/field}
OR - field is in the 'root' of the data model
vs
{$field} - field is at the same level as the control to which the binding applies - You can combine expressions using the JavaScript logical OR and/or the logical AND operators. Note that the logical OR is '||' and the logical AND is '&&'. However, for use in Expression binding, the logical AND must be escaped as '&&'. See examples below for the exact syntax in an expression.
- Comparisons between fields must be done with the ‘is exactly equal to’ variations of the equality operations (3 characters not 2). That is, you must use '===' (but not '==') for equality and '!==' (but not '!=') for inequality.
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