Field Input
Besides the Attention Identifier (AID) keys described on the BMS Terminal page, the runtime forms provide a number of behaviors that control how text is entered into the input fields of a form. These behaviors help reproduce the typing experience of the original mainframe screens.
Auto-Tab
Auto-tab automatically moves the focus to the next enterable field as soon as the current field is completely filled. This mirrors the behavior of a mainframe terminal, where the cursor advances to the next field once a field reaches its defined length.
- The focus advances only when the field is filled to its full defined length.
- Protected (read-only) fields are skipped, so the focus always lands on the next field that accepts input.
- When the last field of a form is filled, the focus wraps around to the first enterable field.
Overtype Mode
Overtype mode determines whether typed characters replace existing content or are inserted into it.
| Mode | Behavior |
|---|---|
| Insert (default) | Typed characters are inserted at the cursor position and push the remaining characters to the right, as in a standard text field. |
| Overtype | Typed characters replace the character at the cursor position and the cursor moves forward. When the cursor reaches the end of the field, no further characters are accepted. |
Overtype mode is a form-level setting. When it is enabled and a field receives focus through auto-tab, the field content is selected so that the next entry overwrites it. When a field is focused with the keyboard, the cursor is placed at the start of an alphanumeric field and at the end of a numeric field. When focus is set by clicking in a field, the cursor stays at the position that was clicked.
info Overtype mode is disabled by default, in which case the fields behave as normal insert-mode text fields.
Numeric Fields
Numeric input fields only accept characters that are valid for a number. Any other key is rejected and has no effect on the field.
- The digits
0–9are always accepted. - A decimal separator is accepted when the field is defined with decimal positions.
- A sign (
+or-) is accepted when the field is defined as signed.
When editing a numeric field with Backspace or Delete, the cursor is repositioned around the
decimal separator and sign so that the remaining number stays correctly aligned.