g_form controls the form in client scripts, UI policies and client UI actions: read and set fields, show messages, and make fields mandatory, read-only or hidden.
g_form.getValue(field)Returns the field value as a string (a sys_id for reference fields).
function onLoad() {
var category = g_form.getValue('category');
}Always a string: use getIntValue() or getDecimalValue() for numbers.
g_form.getIntValue(field) / getDecimalValue(field)Returns the field as a number, ready for comparisons.
function onLoad() {
var quantity = g_form.getIntValue('u_quantity');
if (quantity > 10) {
g_form.showFieldMsg('u_quantity', 'Needs approval', 'info');
}
}g_form.setValue(field, value, displayValue)Sets a field. For reference fields, pass the display value as well to avoid an extra server call.
function onLoad() {
g_form.setValue('urgency', 2);
g_form.setValue('assigned_to', g_user.userID, g_user.getFullName());
}g_form.clearValue(field)Empties a field.
function onLoad() {
g_form.clearValue('u_resolution_code');
}g_form.setMandatory(field, true|false)Makes a field mandatory, or not.
function onLoad() {
var isMajor = g_form.getValue('priority') == '1';
g_form.setMandatory('u_business_impact', isMajor);
}A mandatory empty field cannot be hidden: call setMandatory(field, false) first.
g_form.setReadOnly(field, true|false)Makes a field read-only, or editable.
function onLoad() {
if (!g_form.isNewRecord()) {
g_form.setReadOnly('caller_id', true);
}
}Read-only in the browser is not security; protect the field with an ACL too.
g_form.setDisplay(field, true|false) / setVisible()Shows or hides a field. setDisplay() closes the gap; setVisible() leaves an empty space.
function onLoad() {
var isHardware = g_form.getValue('category') == 'hardware';
g_form.setDisplay('u_asset_tag', isHardware);
}g_form.setSectionDisplay(section, true|false)Shows or hides a form section. The name is the section label in lowercase with underscores.
function onLoad() {
var resolved = g_form.getValue('state') == '6';
g_form.setSectionDisplay('resolution_information', resolved);
}g_form.addInfoMessage() / addErrorMessage() / clearMessages()Shows a message at the top of the form.
function onLoad() {
g_form.clearMessages();
g_form.addInfoMessage('This incident is linked to a major incident.');
}g_form.showFieldMsg(field, message, 'info'|'error') / hideFieldMsg(field)Shows a message under one field.
function onLoad() {
g_form.hideFieldMsg('short_description');
g_form.showFieldMsg('short_description', 'Keep it under 80 characters', 'error');
}g_form.addOption() / removeOption() / clearOptions()Changes the choices of a choice field.
function onLoad() {
g_form.clearOptions('u_size');
g_form.addOption('u_size', '', '-- None --');
g_form.addOption('u_size', 'm', 'Medium');
g_form.addOption('u_size', 'l', 'Large');
}g_form.getReference(field, callback)Loads the record behind a reference field and passes it to the callback.
function onLoad() {
g_form.getReference('caller_id', function(caller) {
if (caller.vip == 'true') {
g_form.addInfoMessage('VIP caller');
}
});
}Always pass a callback. For one field, GlideAjax is lighter: getReference() returns the whole record.
g_form.getUniqueValue() / getTableName() / isNewRecord()The record's sys_id, its table, and whether it has been saved yet.
function onLoad() {
if (g_form.isNewRecord()) {
g_form.setValue('contact_type', 'self-service');
}
}setDisplay(field, false) hides the field and closes the gap. setVisible(field, false) hides it but leaves an empty space where it was.
ServiceNow keeps an empty mandatory field visible so the form can still be saved. Call g_form.setMandatory(field, false) before hiding it.