Prevent Duplicate Submission

function onSubmit() {
  // Check if form is already being submitted
  if (g_form.isUserSubmitting) {
    // Already submitting, prevent duplicate
    alert('This form is already being submitted. Please wait...');
    return false;
  }

  // Validation checks before allowing submission
  var validationErrors = [];

  // Check mandatory fields
  var requiredFields = [
    {name: 'short_description', label: 'Short Description'},
    {name: 'caller_id', label: 'Caller'}
  ];

  requiredFields.forEach(function(field) {
    if (!g_form.getValue(field.name)) {
      validationErrors.push(field.label + ' is required');
    }
  });

  // If validation fails, don't proceed
  if (validationErrors.length > 0) {
    alert('Please correct the following errors:\n\n' + 
          validationErrors.join('\n'));
    return false;
  }

  // Mark form as being submitted
  g_form.isUserSubmitting = true;

  // Disable submit button and related buttons
  // Find and disable all submit-type buttons
  try {
    // Get all form buttons
    var buttons = document.querySelectorAll('button[type="submit"], ' +
                                            'button[name="submit"], ' +
                                            'input[type="submit"]');
    
    buttons.forEach(function(button) {
      button.disabled = true;
      button.style.opacity = '0.5';
      button.style.cursor = 'not-allowed';
      
      // Store original text
      var originalText = button.innerText || button.value;
      button.setAttribute('data-original-text', originalText);
      
      // Update button text to show submission in progress
      if (button.innerText) {
        button.innerText = 'Submitting...';
      } else if (button.value) {
        button.value = 'Submitting...';
      }
    });

    // Also try to disable ServiceNow's specific buttons
    if (typeof gsftSubmit !== 'undefined') {
      // Disable standard save button
      var saveButton = gel('sysverb_insert') || gel('sysverb_update');
      if (saveButton) {
        saveButton.disabled = true;
        saveButton.style.opacity = '0.5';
      }
    }
  } catch (e) {
    console.error('Error disabling buttons:', e);
    // Continue with submission even if button disable fails
  }

  // Show loading message
  g_form.addInfoMessage('Submitting form, please wait...');

  // Set a timeout to re-enable if submission fails
  setTimeout(function() {
    // If we're still on the form after 30 seconds, something went wrong
    if (g_form.isUserSubmitting) {
      g_form.isUserSubmitting = false;
      
      // Re-enable buttons
      var buttons = document.querySelectorAll('button[disabled]');
      buttons.forEach(function(button) {
        button.disabled = false;
        button.style.opacity = '1';
        button.style.cursor = 'pointer';
        
        // Restore original text
        var originalText = button.getAttribute('data-original-text');
        if (originalText) {
          if (button.innerText) {
            button.innerText = originalText;
          } else if (button.value) {
            button.value = originalText;
          }
        }
      });
      
      g_form.clearMessages();
      g_form.addErrorMessage('Submission timed out. Please try again.');
    }
  }, 30000);  // 30 second timeout

  // Allow submission to proceed
  return true;
}