如何在没有按钮的情况下自动保存html textarea？ [关闭]

I have a textarea in my html like this:

<textarea id="area1"></textarea>

When visitors copy/paste or type something in this area i want it to save to a txt file without the visitor having to click any button.

Looked all over the web but can't find any solution.

write JS function, that saves info in .txt file. Let's say, function name is saveToTxt(). Then trigger that function onChange:

<textarea id="area1" onChange="saveToTxt(this);"></textarea>

EDITED

Assume that, saveToTxt() is something like that:

<script>
function saveToTxt(fld) {
    const textAreaValue = fld.value;
    // then use textArea variable as container of textarea-content
    // and then treat it as you want.
}
</script>

This example show how to save content automatically 2s after changing. It can prevent from doing save for every character typed.

var t;
function save() {
  clearTimeout(t);
  t = setTimeout(function() {
    console.log('All changes saved'); // save here
  }, 2000);
}

<textarea onchange="save();" onkeyup="save();"></textarea>

</div>