Change the name of an <output> element:
document.getElementById("myOutput").name = "newOutputName";
Click the button to change the name of the output element.
<!DOCTYPE html> <html> <body> <form oninput="x.value=parseInt(a.value)+parseInt(b.value)">0 <input type="range" id="a" value="50">100 +<input type="number" id="b" value="50"> =<output id="myOutput" name="x" for="a b"></output> </form>//from w w w. j a va 2s .c o m <button type="button" onclick="myFunction()">Test</button> <p id="demo"></p> <script> function myFunction() { document.getElementById("myOutput").name = "newOutputName"; document.getElementById("demo").innerHTML = "The name of the output element was changed."; } </script> </body> </html>