how to focus set up in particular control

<input id="textbox" type="text" onkeypress="return myScript(event)" />

//Add control on which you want to focus,for example:
<input id="targetTxtBox" type="text"/>

//Javascript function:


function myScript(e) {
    if (e.keyCode == 13) {
        var tb = document.getElementById("targetTxtBox");
        tb.focus(); 
        return false;
    }
}