title: Google-apps-script: Simple Check Value - Return Value
body: <p>I have a Google Sheet accepting form responses, and I want to have a value placed in the first blank cell in the row when a response arrives. </p>
  
  <p>For example, when this script sees a response arrive from the form in row 15, and if the last value from the form fills cell D15, it should place an "X" in cell E15.</p>
  
  <p>I have built apps with php, but am a javascript newb. Can anyone point me in the right direction for ideas of how to approach this in Google Sheets/Scripts? </p>
  
  <p>Here is what I have so far:</p>
  
  <pre><code>function ?(event) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  
  //if form is submitted
  if (event.?values[?] == '?') {
  //Add "X" to the first empty cell in the row
  ?.?("x");
  }
  }
  </code></pre>
  
  <p>I have added "?"s where I am stuck.  Many thanks in advance for any help!</p>