How to get the value of the select drop-down box (option has no and value attributes)_javascript skills

How to get the value of the select drop-down box:
1. When the option of the drop-down box has no value attribute

Copy the code The code is as follows:

Student ID
Name
< ;option>age

<script> <br>window.onload = funciton(){ <br>var param = document.getElementById("param1"); <br>param.onchange = getParam(){ <br>var text = param.value; <br>} <br>} <br></script>

2. Drop-down box When the option has a value attribute

Copy the code The code is as follows:

Student ID
Name
Age

<script> <br>window.onload = funciton(){ <br>var param = document.getElementById("param1"); <br>param.onchange = getParam(){ <br>var selectIndex = param.selectIndex; //Get the index number of the option <br>var text = param.options[selectIndex].text; <br></script>