JS gets the value in the first element in the select drop-down box-JS Tutorial-php.cn

JS gets the value in the first element in the select drop-down box

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Release： 2018-03-23 16:54:46

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This time I will bring you JS to get the value in the first element in the select drop-down box, and JS to get the value in the first element in the select drop-down box. What are the things to note? are as follows. This is a practical case, let’s take a look at it.

The example of this article describes the method of JavaScript to obtain the first value in the select drop-down box. Share it with everyone for your reference, the details are as follows:

1. Description

Get the first value in the select drop-down box

2. Implement the source code

<!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>JavaScript获取select下拉框中的第一个值</title>
<script type="text/javascript">
   /**
   * JavaScript获取select下拉框中的第一个值
   */
   function getFirstValOfSelect()
   {
     //获取select中的ID
     var selectId = document.getElementById("select_option");
     //获取select下拉框中第一个值
     var selectValue = selectId.options[0].value;
     //获取select下拉框中第一个文本值
     var selectText = selectId.options[0].text;
     //打印select下拉框中第一个值和文本值
     alert("值：" + selectValue + "\n" + "文本值：" + selectText);
   }
</script>
</head>
<body>
  <p id="p_select">
    <select id="select_option">
      <option value="0">桃树</option>
      <option value="1">梨树</option>
      <option value="2">樟树</option>
      <option value="3">枫树</option>
      <option value="4">松树</option>
      <option value="5">梧桐树</option>
      <option value="6">槐树</option>
    </select>
  </p>
  <input type="button" value="JavaScript获取select下拉框中的第一个值" onclick="getFirstValOfSelect()"/>
</body>
</html>

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3. Implement the result

(1) Select the first item

(2) Select the second item

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