While utilizing ASP.NET to pass a value to a JavaScript function, I encountered an issue where it doesn't seem to work when trying to pass a value from another control. It seems to behave as if there is a syntax error and just reverts back to the main form.
Does anyone have insight into why this might be happening?
Example:
<asp:TextBox ID="txtToSay" runat="server" Text="Something"></asp:TextBox>
<asp:Button runat="server" ID="btnSaySomething1" Text="Say Something"
OnClientClick="saySomething(<%=txtToSay.Text%>);" /> <!-- doesn't work -->
<asp:Button runat="server" ID="btnSaySomething1" Text="Say Something"
OnClientClick="saySomething('<%=txtToSay.Text%>');" /> <!-- doesn't work -->
<asp:Button runat="server" ID="btnSaySomething2" Text="Say Something"
OnClientClick="saySomething('Something');" /> <!-- works -->
<script type="text/javascript">
function saySomething(txt){
alert(txt);
};
</script>
Additional Information:
This web application is running on .NET 4.0.
Programming Language Used: C#
Update:
After spending some time troubleshooting this issue, I discovered that <%%> tags cannot be used in ASP controls. Moreover, if you are looking for dynamic evaluation of control values, it's advised to avoid using <%=someControl.Text%> or similar constructs since they are only evaluated once a request is made to the server. If you require a static value from another control at runtime, consider setting that value in the page load event or finding an alternative approach in the code behind.