Mobile Form Expression Fundamentals for Field Service Management

Form layout and behavior are defined by element properties. A property can contain a static value or, where supported, an expression.

The following element uses static values for its label, type, and placeholder:

          {
  "actions": {
    "label": "Actions Taken",
    "type": "textarea",
    "placeholder": "Enter details here..."
  }
}

To make a property responsive to form data, assign a JavaScript expression that references at least one element property.

This topic includes the following sections:

Mobile Form Expression Evaluation and Updates - Explains when expressions run, how dependencies trigger updates, and how results are assigned to element properties.
Mobile Form Expression Requirements and Restrictions - Lists the rules for property references, structural properties, expected data types, JavaScript identifiers, and consistent results.
Value Expression Behavior in Mobile Forms - Explains how the value property calculates initial values, retains saved overrides, and recalculates after a dependency changes.