googleDriveScript.js

/**
 * The onOpen function runs automatically when the Google Docs document is
 * opened. Use it to add custom menus to Google Docs that allow the user to run
 * custom scripts. For more information, please consult the following two
 * resources.
 *
 * Extending Google Docs developer guide:
 *     https://developers.google.com/apps-script/guides/docs
 *
 * Document service reference documentation:
 *     https://developers.google.com/apps-script/reference/document/
 */

function onOpen() {
 DocumentApp.getUi().createMenu('Template Tags')
  .addItem('Replace Me!', 'replaceMe')
  .addToUi();
}


function replaceMe () {
 var result = DocumentApp.getUi().prompt('What do you want to change {{REPLACE_ME}} to?', DocumentApp.getUi().ButtonSet.OK_CANCEL);
 var responseText = null;
  if(result.getSelectedButton() == DocumentApp.getUi().Button.OK){
    responseText = result.getResponseText();
    if (responseText.length > 0) {
      var bodyElement = DocumentApp.getActiveDocument().getBody();
      bodyElement.replaceText('{{REPLACE_ME}}', responseText);
    }
  }
}