Simulate Enter In JavaScript

Question

I try to simulate Enter in JavaScript in a specific TextArea. This is my code:

 function enter1() {
       var keyboardEvent = document.createEvent('KeyboardEvent'); 
       var initMethod = typeof keyboardEvent.initKeyboardEvent !== 'undefined' ? 'initKeyboardEvent' : 'initKeyEvent'; 
       keyboardEvent[initMethod]('keydown', // event type : keydown, keyup, keypress
            true, // bubbles
            true, // cancelable
            window, // viewArg: should be window
            false, // ctrlKeyArg
            false, // altKeyArg
            false, // shiftKeyArg
            false, // metaKeyArg
            13, // keyCodeArg : unsigned long the virtual key code, else 0
            13 // charCodeArgs : unsigned long the Unicode character associated with the depressed key, else 0
       );
       document.getElementById('text').dispatchEvent(keyboardEvent);
 }

TextArea:

<textarea id="text"> </textarea>

When I call enter1(), it doesn't do anything in the TextArea. Why is this?

Answer 1

I think it's a browser bug since keyboardEvent.which is unwritable. In order to fix it, you have to delete keyboardEvent.which property before assigning the keycode.

 function enter1() {
   var keyboardEvent = document.createEvent('KeyboardEvent');
   delete keyboardEvent.which;
   var initMethod = typeof keyboardEvent.initKeyboardEvent !== 'undefined' ? 'initKeyboardEvent' : 'initKeyEvent';
   keyboardEvent[initMethod](
     'keydown', // event type : keydown, keyup, keypress
     true, // bubbles
     true, // cancelable
     window, // viewArg: should be window
     false, // ctrlKeyArg
     false, // altKeyArg
     false, // shiftKeyArg
     false, // metaKeyArg
     13, // keyCodeArg : unsigned long the virtual key code, else 0
     13 // charCodeArgs : unsigned long the Unicode character associated with the depressed key, else 0
   );
   document.getElementById('text').dispatchEvent(keyboardEvent);
 }

An alternative solution is KeyboardEvent Constructor. Just be careful with the compatibility issue.

 function enter1() {
   var keyboardEvent = new KeyboardEvent('keydown');
   delete keyboardEvent.which;
   keyboardEvent.which = 13;
   document.getElementById('text').dispatchEvent(keyboardEvent);
 }