从动态文本区域获取值

var body = "Descripción";
//use `^=` to denote that the attribute should start with a string
var _body = $("textarea[title^='" + body + "']");

console.log(_body.val());

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<textarea rows="10" cols="20" id="Descripci_x00f3_n_9b68a148-3221-43c6-abf3-bb32afd3e51b_$TextField" title="Descripción Campo obligatorio" class="ms-long">
  Stuff
</textarea>

function run() {
    var textbox = document.getElementById("Descripci_x00f3_n_9b68a148-3221-43c6-abf3-bb32afd3e51b_$TextField").value;
    document.write(textbox);
}
</script>

<textarea rows="10" cols="20" id="Descripci_x00f3_n_9b68a148-3221-43c6-abf3-bb32afd3e51b_$TextField" title="Descripción Campo obligatorio" class="ms-long"></textarea>
<br/>
<button type="button" onclick="run()">get</button>