javascript - 如何在 JavaScript 中连续增加或减少值

Question

当鼠标在元素上单击并按住时，我想增加或减少值，它可以工作但不能在鼠标按住时工作

var salainv = document.getElementById("sala").value;
var bodegainv = document.getElementById("bodega").value;

function incrementar() {
  document.getElementById("sala").value = salainv++;
  document.getElementById("bodega").value = bodegainv--;
}

function decrementar() {
  document.getElementById("sala").value = salainv--;
  document.getElementById("bodega").value = bodegainv++;
}

<input type="number" name="bodega" id="bodega" value="15">
<input type="number" name="sala" id="sala" value="5">
<img src="https://cdn.pixabay.com/photo/2012/04/13/00/21/plus-31216_960_720.png" style="width: 40px;" onClick="incrementar()">
<img src="http://images.clipartpanda.com/minus-clipart-RTA7dagTL.png" style="width: 40px;" onClick="decrementar()">

谁能帮我让它在按下鼠标时工作？

谢谢。

Answer 1

您可以使用 setInterval如下所示以及 onMouseDown 和 onMouseUp 事件

var salainv = document.getElementById("sala").value;
var bodegainv   = document.getElementById("bodega").value;

var timerId;
function incrementar() {
      document.getElementById("sala").value = salainv++;    
      document.getElementById("bodega").value = bodegainv--; 
 }
 function beginIncrementar(){
     timerId = setInterval(incrementar,200);
 }
 function endIncrementar(){
     clearInterval(timerId)
 }
 function decrementar() {
      document.getElementById("sala").value = salainv--;
      document.getElementById("bodega").value = bodegainv++; 
 }
 
 function beginDecrementar(){
     timerId = setInterval(decrementar,200);
 }
 function endDecrementar(){
     clearInterval(timerId)
 }

<input type="number" name="bodega" id="bodega" value="15">
<input type="number" name="sala" id="sala" value="5">
<img src="https://cdn.pixabay.com/photo/2012/04/13/00/21/plus-31216_960_720.png" style="width: 40px;" onClick="incrementar()" onMouseDown="beginIncrementar()" onMouseUp="endIncrementar()">
<img src="http://images.clipartpanda.com/minus-clipart-RTA7dagTL.png" style="width: 40px;" onClick="decrementar()" onMouseDown="beginDecrementar()" onMouseUp="endDecrementar()">