Why doesn't the JavaScript populate the text box here?

Question

I have googled this quite a lot and must still be missing something. The method creates the pop-up dialog fine but the text box does not get populated when I press the button.

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Test.aspx.cs" Inherits="Proj1.Test" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">
        function ButtonSubmit() {
            var isPressed = document.getElementById('SubmitPressed');
            isPressed.Value = "True";
            alert('You have submitted your request. ');           
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <asp:TextBox ID="SubmitPressed" runat="server"></asp:TextBox>
            <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="ButtonSubmit();"/>
        </div>
    </form>
</body>
</html>

Does this answer your question? [getElementById not finding control generated by ASP.net](https://stackoverflow.com/questions/4595823/getelementbyid-not-finding-control-generated-by-asp-net) — vahdet, Dec 13 '19 at 10:51
What is this? `isPressed.Value` supposed to do? How is that supposed to work? — VDWWD, Dec 13 '19 at 10:55
@VDWWD I want to send the text value to the text box which I will hide and pull the value into code behind — Salbrox, Dec 13 '19 at 12:13
Yes, but what makes you think using `Value` will assign the value to the TextBox? Javascript is case sensitive! — VDWWD, Dec 13 '19 at 12:22
@VDWWD I used document.getElementById('SubmitPressed').value = "True"; and it worked, thank you. — Salbrox, Dec 13 '19 at 12:25

Dan-J · Answer 1 · 2019-12-14T05:52:55.093

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">
        function ButtonSubmit() {
            var isPressed = document.getElementById('SubmitPressed');
            isPressed.value = "True";
            alert('You have submitted your request. ');
            return false;
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="SubmitPressed" ClientIDMode="Predictable" runat="server"></asp:TextBox>
        <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="ButtonSubmit();"/>
    </div>
    </form>
</body>
</html>

Try above code in place of your existing textbox

score 0 · Accepted Answer · answered Dec 13 '19 at 12:28

0

I needed to change .Value to .value since Javascript is case sensitive as per @VDWWD's comment.

var isPressed = document.getElementById('SubmitPressed');
isPressed.value = "True";

answered Dec 13 '19 at 12:28

Salbrox

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Why doesn't the JavaScript populate the text box here?

2 Answers2