Custom TextField,how to read data

I created a Custom Textfield with WebControlWrapper super class
this is the code in SetupHTML :

[code] dim tmp as string
tmp = “<div id=”""+self.ControlID + “”">"
tmp = tmp +"<input type="“text”" name = ““firstname”” placeholder = “+ Placeholder+”">"
tmp= tmp+""

return tmp

how can i read the input text data like native textfield?For example like “Textfield.Text”

You will need to use JavaScript and capture one of the events like keyup, keydown, keypress, or change and then send the data back to the server with the triggerServerEvent JavaScript method.

Can you make an example?