Gravity Forms: add the READONLY property to an input UNTIL it gets a value set

gf-readonly-until-value.js

/*
* This snippet: https://gist.github.com/cliffordp/c0b48b14f0f6f42d27c79e8f39013774
* WHAT: This adds the READONLY property to an input field and then removes it AFTER this same field has a value in it.
* WHY: Useful when a text field gets a dynamically-filled value but you want the input to remain editable thereafter.
* EXAMPLE: a custom County text field that gets filled upon selecting a different field's Address Autocomplete.
* HOW-TO:
* 1. Paste this snippet into https://gravitywiz.com/gravity-forms-code-chest/ (this code is formatted for use in that plugin).
* 2. Add the `readonly-until-value` class to any text input field (not tested on other field types).
* 3. Alternatively, add a class like `readonly-until-value-17` to make Field#17 (the Address Autocomplete field) focused (outlined) upon clicking the readonly field.
*/
gform.addAction("gfcc_deferred", function () {
	jQuery("#gform_GFFORMID .gfield").each(function () {
		var classes = jQuery(this).attr("class") || "";
		var match = classes.match(/readonly-until-value(?:-(\d+))?(?:\s|$)/);
		if (!match) return;

		var sourceFieldId = match[1] || null;
		var $input = jQuery(this).find("input");
		var $field = jQuery(this);

		$input
			.prop("readonly", true)
			.attr("title", "first, enter the Full Address");

		// Hidden until value is set — no layout shift
		$field.css("visibility", "hidden");

		if (sourceFieldId) {
			$input.on("focus", function () {
				jQuery("#input_GFFORMID_" + sourceFieldId).focus();
			});
		}

		$input.on("change", function () {
			if ($input.val()) {
				$field.css("visibility", "");
				$input
					.prop("readonly", false)
					.removeAttr("title")
					.off("change focus");
			}
		});
	});
});