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How to operate JS to realize drop-down box linkage

php中世界最好的语言Original: 2018-05-30 11:13:291804browse

This time I will show you how to operate JS to achieve drop-down box linkage. What are the precautions for operating JS to achieve drop-down box linkage? The following is a practical case, let’s take a look.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS下拉联动</title>
<script>
function setSecond(obj){
  var val = obj.value;
  if(val == 'en'){
    var sec = document.getElementById('second');
    sec.innerHTML = "<option>one</option><option>two</option>";
  }else{
    var sec = document.getElementById('second');
    sec.innerHTML = "<option>一</option><option>二</option>";
  }
}
</script>
</head>
<body>
<p>
  <select id="first" onchange="setSecond(this)">
    <option value="en">en</option>
    <option value="zh">zh</option>
  </select>
</p>
<p>
  <select id="second">
  </select>
</p>
</body>
</html>

Use innerHTML,

IE browser does not support this method, so the improvement method:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title> JS下拉联动</title>
<script>
function setSecond(obj){
  var val = obj.value;
  if(val == 'en'){
    var sec = document.getElementById('second');
    sec.options[0] = new Option("one","one");
    sec.options[1] = new Option("two","two");
  }else{
    var sec = document.getElementById('second');
    sec.options[0] = new Option("一","one");
    sec.options[1] = new Option("二","two");//可设置循环配置，也可一个一个配置
  }
}
</script>
</head>
<body>
<p>
  <select id="first" onchange="setSecond(this)">
    <option value="en">en</option>
    <option value="zh">zh</option>
  </select>
</p>
<p>
  <select id="second">
  </select>
</p>
</body>
</html>

I believe you have mastered the method after reading the case in this article, more Please pay attention to other related articles on the php Chinese website!

How to operate JS to realize drop-down box linkage

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