如何在jQuery中禁用重复的keydown [英] How to disable repetitive keydown in jQuery

问题描述

当用户按下某个键时，我希望keydown（）事件只被调用一次，但是在用户停止按键之前调用它。

When user keeps a key pressed, I want the keydown() event get called only once, but its called until user stops pressing the key.

这是什么我正在尝试：

   $(document).keydown(function(event){
     var keycode = (event.keyCode ? event.keyCode : event.which);
     if(keycode == '39'){
              $("#box").animate({"left": "+=30px"}, "fast");
     } 
   });  

因此，当用户按下右箭头键时，我希望div＃框向右移动30px 。它会移动，但是如果用户按下键，它就会飞走。

So, when user presses right arrow key, I want the div#box to move 30px to the right. It moves but if user keeps key pressed it flies away.

我需要它每次按下只移动30px，并且即使用户按下按键也停止。你知道它是如何实现的吗？

I need it to move only by 30px per press, and stop, even if user keeps the key pressed. Do you know how it can be accomplished?

推荐答案

跟踪哪些键已关闭，并忽略键码39，直到键盘为止清除它：

Keep track of which keys are down, and ignore keycode 39 until a keyup even clears it:

var down = {};

$(document).keydown(function(event){
     var keycode = (event.keyCode ? event.keyCode : event.which);
     if(keycode == '39'){
          if (down['39'] == null) { // first press
              $("#box").animate({"left": "+=30px"}, "fast");
              down['39'] = true; // record that the key's down
          }
     } 
   });

$(document).keyup(function(event) {
     var keycode = (event.keyCode ? event.keyCode : event.which);
     down[keycode] = null;
});

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