Attach JavaScript to a server control

This .aspx page has a text box and a button. When you enter your name in TextBox1 and click Button1, the JavaScript function showName() is supposed to run on the client to show an alert box with the name entered. But VWD won't show the page in the browser.

How can I wire the JavaScript code to Button1?

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>

<script type="text/javascript">
function showName() {
       alert ("Hello " + '<%= TextBox1.Text%>');
}
</script>

</head>
<body>
<form id="form1" runat="server">

Please enter your name:<br />

      <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 

<asp:Button ID="Button1" runat="server" Text="OK" OnClick="showName()" />

</form>
</body>
</html>

MBarongan

Asked: 2014-01-26

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2 Solutions

LVL 4

ravikantninaveCommented: 2014-01-26

<asp:Button ID="Button1" runat="server" Text="OK" OnClientClick="return showName();" />

<script language="javascript" type="text/javascript">
function showName() {

alert('hello ' + document.getElementById("<%=TextBox1.ClientID%>").value);
}

LVL 84

Dave BaldwinFixer of ProblemsCommented: 2014-01-26

The correct value does not exist on the server so <%=TextBox1.ClientID%> doesn't do anything useful. You have to get the value in javascript using the 'id' of the element.

<script type="text/javascript">
    function showName() {
      alert('hello ' + document.getElementById("TextBox1").value);
      }
</script>

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LVL 4

ravikantninaveCommented: 2014-01-26

I tried the code and it works perfectly. Check

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script language="javascript" type="text/javascript">
    function showName() {
alert('hello ' + document.getElementById("<%=TextBox1.ClientID%>").value);
} 
</script>

</head>
<body>
    <form id="form1" runat="server">
    <div>
    Please enter your name:<br />
                                          
      <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>&nbsp;

      <asp:Button ID="Button1" runat="server" Text="OK" OnClientClick="return showName();" />
    </div>
    </form>
</body>
</html>

Open in new window

MBaronganAuthor Commented: 2014-01-26

Thank you for both versions in the script, ("Textbox1").value and ("<%= TextBox1.ClientID%>").value. The thing I was curious about the most was how to wire it up with Button1, OnClientClick="return showName();"

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Attach JavaScript to a server control

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