Setting the default Button for a TextBox in ASP.NET

Hitting the enter key in a TextBox can sometimes have undesired effects like the wrong submit Button being “clicked“. The method described below allows you to specify a default Button to submit when the user hits the enter key in a TextBox.

When you press a key on your keyboard, the js OnKeyPress event is fired. This calls a function to which we pass the id of the button associated with the TextBox. The function gets a reference to the button and simuilates a mouse-click on the Button. We perform a browser detection because IE and Netscape have different event models. The function finally returns false so that the keypress event is cancelled (otherwise a second form submit will be raised). This works with newer versions of IE/Netscape.

function clickButton(e, buttonid){

      var evt = e ? e : window.event;

      var bt = document.getElementById(buttonid);

      if (bt){

          if (evt.keyCode == 13){

                bt.click();

                return false;

          }

      }

}

//code behind
TextBox1.Attributes.Add("onkeypress", "return clickButton(event,'" + Button1.ClientID + "')");

The code behind generates the following code:

<input name="TextBox1" type="text" id="TextBox1" onkeypress="return clickButton(event,'Button1')"  />

This causes web control Button1 to be clicked when the enter key is hit inside TextBox1.