Question

When the user submits the form, writeToStorage is fired and it checks if the user is in localStorage and if it is, an alert is run. After this alert I don’t want the action to execute. I tried return false; but obviously that does not stop the python script from running. How do I stop the action of the form in case the alert is triggered?

function writeToStorage() { 
  var chooser = localStorage.getItem("chooser");
  if (chooser) {
    alert("you are already a user);
    //return false; }
  else {
    //the rest of the program } };

# if alert is run the action of the form should not run
<form name="choice_form" id="choice_form" action="/g/choicehandler" method="post" onsubmit="writeToStorage()">
  <textarea name="choice" rows="7" cols="50"></textarea><br />
  <input type="hidden" name="chooser" id="form_chooser" />
  <input type="submit" value="submit your choice">
</form>

Answer 1

Add your return false back in and also change:

onsubmit="writeToStorage()"

To:

onsubmit="return writeToStorage();"