ASP.NET single quotes are converted to '

Question

Note: Most probably this will be a double question, but since I haven't found a clear answer, I'm asking it anyway.

In ASP.NET I'd like to add some JavaScript to the onclick event of a CheckBox. I've simplified the case to this:

<asp:CheckBox ID="TestCheckBox" runat="server" onclick="alert('test');" Text="Test" />

The resulting HTML is as follows:

<input id="MainContainer_TestCheckBox" type="checkbox" name="ctl00$MainContainer$TestCheckBox" onclick="alert(&#39;test&#39;);" /><label for="MainContainer_TestCheckBox">Test</label> 

What particularly bothers me is that a single quote 'automatically' gets converted into '''. If I omit the onclick in the markup and assign it in Page_Load, the exact same results show in the HTML.

protected void Page_Load(object sender, EventArgs e)
{
    this.TestCheckBox.Attributes["onclick"] = "alert('test');";
}

Anyone got a clue about what's happening? Or how to fix/ avoid it?

Answer 1

First of all the asp check box control doesn't take onclick as a valid attribute.

So you can do two things:

1- If you don't need the value server-side, you can just put a normal check box instead of the asp check box.

2- If you need the value server side, add the runat="server" attribute and place and ID on your check box so you can reference it in your code.

<input type="checkbox" id="chk1" onclick="alert('hello');" runat="server" />

Answer 2

We had the same issue with single quotes in attribute values when we migrated a project from .NET 3.5 to .NET 4.0. It converts all single quotes in attribute values to &39;. So we went back to .NET 3.5.

It's a .NET 4.0 thing. You can read more about this issue here.