如何在发出警报后取消表单的操作？

Question

当用户提交表单时，会触发writeToStorage并检查用户是否在localStorage中，如果是，则运行警报。在此警报之后，我不希望该操作执行。我试过return false;，但显然这并没有阻止python脚本运行。如果触发警报，如何停止表单的操作？

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

重新添加return false并更改：

onsubmit="writeToStorage()"

要：

onsubmit="return writeToStorage();"