模拟输入JavaScript

Question

我试图模拟在JavaScript在一个特定TextArea。 代码：

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> 

当我打电话ENTER1（）什么都不干的textarea的。为什么？

Answer 1

我认为这是一个浏览器bug，因为keyboardEvent.which是不可写的。为了解决这个问题，你必须在分配键码之前删除keyboardEvent.which属性。

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); 
} 

另一种解决方案是KeyboardEvent Constructor。只要注意兼容性问题。

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