qrcode
HTML
<script src="https://raw.github.com/jeromeetienne/jquery-qrcode/master/jquery.qrcode.min.js"></script>
<div id="qr"></div>
<textarea id="encode-text"></textarea>
<button id="qr-btn">qrcode</button>
<button id="reset">reset</button>
JavaScript
$(function(){
$("#qr-btn").on("click",function(){
$("#qr").qrcode($("#encode-text").val());
});
$("#reset").on("click",function(){
$("#encode-text").val("");
});
});