如何使用JavaScript更改ASP标签中的值

Question

I have create a function onchange when there a textbox value change. I able to show the result into label using innerHTML using Javascript. But when come to code behind, ASP.Net VB is not able to get the label.text value. Is there any way to show the result in this label?

<asp:Label ID="lblreserve1" runat="server" text="**HERE**" Visible="true"></asp:Label>
<input type="text" name="reservation-time" id="reservation-time" class="form-control" value="01/01/2016 - 01/25/2016" onchange="myFunction1(this.value)"/>

function myFunction1(reservedate) {
  var x = document.getElementById("reservation-time").value;
  document.getElementById("<% =lblreserve1.clientID %>").innerText = x;
}

MsgBox(lblreserve1.Text)

Answer 1

I think this is an XY problem. I don't think you want to change that label.

I imagine you have a textbox that is serving double duty. If the label says one thing, the textbox contains data that means one thing; if the label says something else, the textbox contains some other data. This is a really unusual way to accomplish what is a very common web UX.

Instead, create a series of label/textbox pairs and enclose them in DIV elements. Hide all DIVs but one of them. When you wish to "change" the label, unhide the DIV containing the label/textbox you want, and hide everything else.

When the form posts back to the server, all three textboxes will post back too. The server can tell which label was shown because its textbox will contain a value. Thus the server can infer the value of the label that was being shown when the form was submitted.