Append semicolon on pressing enter key in asp.net textbox

How to add a semicolon to the text in asp.net text box (web application), on pressing enter and move the cursor to next line?

Answer

Here is a solution using pure JavaScript.

HTML

<asp:TextBox ID="DemoTextBox" runat="server" 
        CssClass="textarea"
        TextMode="MultiLine"/>

Code Behind (onclick javascript event wire up)

protected void Page_Load(object sender, EventArgs e)
{
    if(!IsPostBack)
    {
        DemoTextBox.Attributes.Add("onkeypress", "AppendSemiColon(this, event)");
    }
}

JavaScript

function AppendSemiColon(objTextBox, evt) {
    if (evt.keyCode == 13) {
        objTextBox.value += ";";
    }
}