动态计算器Javascript [英] Dynamical Calculator Javascript

问题描述

这是一个计算器，它具有我想要取值（1,2,3等）和两个字段的跨度：第一个用于显示用户输入的内容，第二个用于计算结果。
问题如何获取值，所以当我点击跨越它将显示在第二个领域

这是代码。
http://jsfiddle.net/ovesyan19/vb394983/2/ p>

 < span>（< / span> 
< span>）< / span> 
< span class =delete>←< / span> 
< span class =clear> C< / span> 
< span> 7< / span> 
< span> 8< / span> 
< span> 9< / span> 
< span class =operator>÷< / span> 
 .... 
  

JS：

  var keys = document.querySelectorAll（。keys span）; 
 
 keys.onclick = function（）{
 for（var i = 0; i< key.length; i ++）{
 alert（keys [i] .innerHTML） ; 
}; 
} 
  

解决方案

  var keys = document.querySelectorAll（。keys span）; 
 
 for（var i = 0; i< keys.length; i ++）{
 keys [i] .onclick = function（）{
 alert（this.innerHTML） ; 
 
 
 $ / code $ / pre 
 $ b $ 键是一个 NodeList ，所以你不能附加 onclick 就可以了。您需要通过循环将其附加到该列表中的每个元素。为了获得价值，您可以简单地使用 this.innerHTML 。
 
 
 
 小提琴 
 
It is a calculator which has spans from which I want to take a values(1,2,3, etc.) and two fields: First for displaying what user is typing and the second is for result of calculation.
The question how to get values so when I click on spans it will show it in the second field

Here is the code.
http://jsfiddle.net/ovesyan19/vb394983/2/
<span>(</span>
<span>)</span>
<span class="delete">←</span>
<span class="clear">C</span>
<span>7</span>
<span>8</span>
<span>9</span>
<span class="operator">÷</span>
....
JS:
var keys = document.querySelectorAll(".keys span");

keys.onclick = function(){
    for (var i = 0; i < keys.length; i++) {
        alert(keys[i].innerHTML);
    };
}

解决方案
var keys = document.querySelectorAll(".keys span");

for (var i = 0; i < keys.length; i++) {
    keys[i].onclick = function(){
        alert(this.innerHTML);
    }
}
keys is a NodeList so you cannot attach the onclick on that. You need to attach it to each element in that list by doing the loop. To get the value you can then simple use this.innerHTML.

Fiddle

                        
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