我需要帮助来简化这个下拉功能答案

【问题标题】：I need help simplifying this dropdown function我需要帮助来简化这个下拉功能
【发布时间】：2016-01-07 17:05:21
【问题描述】：

有没有办法进一步简化这个 javascript 函数？为下拉菜单输入 4 个变量似乎有点荒谬，当我想要超过 1 个按钮时，很难跟踪变量。

代码如下：

<!DOCTYPE html>
<html>
<head>
<style>

.dropbtn:hover, .dropbtn:focus {
    background-color: #3e8e41;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
}

.dropdown-content a {
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.dropdown a:hover {background-color: #f1f1f1}
.show {display:block;}

</style>
</head>
<body>

<h2>Clickable Dropdown</h2>
<p>Click on the button to open the dropdown menu.</p>

<div class="dropdown">
<button onclick="myFunction('dropdown-content','myDropdown','show','.dropbtn')" class="dropbtn">Dropdown</button>
  <div id="myDropdown" class="dropdown-content">
    <a href="#home">Home</a>
    <a href="#about">About</a>
    <a href="#contact">Contact</a>
  </div>
</div>

<script>
/* When the user clicks on the button, 
toggle between hiding and showing the dropdown content */
function myFunction(dropDownClass,dropDownId,show,dropbtnClass) {
    var dropdowns = document.getElementsByClassName(dropDownClass);
    var i;     
    var openDropdown = dropdowns[i];
document.getElementById(dropDownId).classList.toggle(show);

// Close the dropdown if the user clicks outside of it
window.onclick = function(event) {
  if (!event.target.matches(dropbtnClass)) {
    for (i = 0; i < dropdowns.length; i++) {
      if (openDropdown.classList.contains(show)) {
        openDropdown.classList.remove(show);
      }
    }
  }
}

}
</script>

</body>
</html>

【问题讨论】：

要求重构工作代码？ -> codereview.stackexchange.com

标签： javascript html css

【解决方案1】：

你是说

window.onload=function() {
  var btns = document.querySelectorAll(".dropbtn");
  for (var i=0;i<btns.length;i++) {
    btns[i].onclick=function() {
      document.getElementById(this.getAttribute("data-drop")).classList.toggle("show");
    }   
  }  
}

.dropbtn:hover,
.dropbtn:focus {
  background-color: #3e8e41;
}
.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
}
.dropdown-content a {
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}
.dropdown a:hover {
  background-color: #f1f1f1
}
.show {
  display: block;
}

<h2>Clickable Dropdown</h2>
<p>Click on the button to open the dropdown menu.</p>

<div class="dropdown">
  <button data-drop="myDropdown1" class="dropbtn">Dropdown</button>
  <div id="myDropdown1" class="dropdown-content">
    <a href="#home">Home 1</a>
    <a href="#about">About 1</a>
    <a href="#contact">Contact 1</a>
  </div>
  <button data-drop="myDropdown2" class="dropbtn">Dropdown</button>
  <div id="myDropdown2" class="dropdown-content">
    <a href="#home">Home 2</a>
    <a href="#about">About 2</a>
    <a href="#contact">Contact 2</a>
  </div>
</div>

【讨论】：

不。 Vanilla JS（纯 JavaScript）