Implement CI validation on change event

Author: hanna-g-sn

Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/catalog_ci_validate_onchange.js

@@ -0,0 +1,31 @@
+function onChange(control, oldValue, newValue, isLoading) {
+  if (isLoading) return;
+
+  var VAR_NAME = 'ci'; // replace with your CI variable name
+
+  // Clear old messages and re-enable submit by default
+  g_form.clearMessages();
+  if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(true);
+
+  var ciSysId = g_form.getValue(VAR_NAME);
+  if (!ciSysId) return;
+
+  var ga = new GlideAjax('CIValidationAjax');
+  ga.addParam('sysparm_name', 'validateCi');
+  ga.addParam('sysparm_ci', ciSysId);
+
+  ga.getXMLAnswer(function(answer) {
+    try {
+      var res = JSON.parse(answer || '{}');
+      if (res.valid) {
+        g_form.addInfoMessage('CI is valid and supported: ' + (res.display || ciSysId));
+      } else {
+        g_form.addErrorMessage(res.message || 'Selected CI is not valid for this request.');
+        if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(false);
+      }
+    } catch (e) {
+      g_form.addErrorMessage('Validation failed. Please try again or choose another CI.');
+      if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(false);
+    }
+  });
+}