在Enter键上动态发布contenteditable div值到Database

Question

I want to post the value of this contenteditable div dynamically to the database with Enter key.

Anyone to help please?

<form method="POST" id="form_<?php echo $s; ?>">
<div class="r">
    <textarea id="\'r_<?php echo $s; ?>\'" style="display: none;"></textarea>
    <div contenteditable="true" class="r_e" holder="Write comment here..." id="r_<?php echo $s; ?>" onkeypress="enterKey(\'<?php echo $s; ?>\',\'r_<?php echo $s; ?>\')"></div>
</div>
<button id="rBtn_<?php echo $s; ?>" onclick="rs(\'<?php echo $s; ?>\',\'<?php echo $f; ?>\',\'r_<?php echo $s; ?>\',this)" style="position: absolute; height: 0px; width: 0px; border: none; padding: 0px;" hidefocus="true" tabindex="-1"></button>

<script type="text/javascript">

 function enterKey(a, b) {

    window.addEventListener("keypress", function (event) {
        var content = document.getElementById("r_"+a).innerHTML;
        $("textarea#r_"+a) = content;
        var button = document.getElementById("rBtn_"+a);
        if(event.keyCode == 13) {
            event.preventDefault();
            button.click(); 
        }
    });
}
</script>