Detailed explanation of the usage of select in JS and jQuery_javascript skills

1.js

var obj=document.getElementById(selectid);
obj.options.length = 0; //清除所有内容
obj.options[index] = new Option("three",3); //更改对应的值
obj.options[index].selected = true; //保持选中状态
obj.add(new Option("4","4")); ”文本",”值"
var index = obj.selectedIndex;obj.options.remove(index);//删除选中项

2.jquery

$("#select_id").append("<option value='Value'>Text</option>"); //为Select追加一个Option(下拉项)
$("#select_id").").find('option:selected').text(); 获取select选中的text
$("#select_id").val(); 获取select选中的value
$("#select_id option[index='0']").remove();//删除索引值为0的Option
$("#select_id option[value='3']").remove(); //删除值为3的Option
$("#select_id option[text='4']").remove(); //删除TEXT值为4的Option
$("#mselect_id").change(function(){
//添加所需要执行的操作代码
})

Supplement: js gets the value selected by the select tag

var obj = document.getElementByIdx_x(”testSelect”); //定位id
var index = obj.selectedIndex; // 选中索引
var text = obj.options[index].text; // 选中文本
var value = obj.options[index].value; // 选中值

Get the selected select value in jQuery

The first way

$('#testSelect option:selected').text();//选中的文本
$('#testSelect option:selected') .val();//选中的值
$("#testSelect ").get(0).selectedIndex;//索引

The second way

$("#tesetSelect").find("option:selected").text();//选中的文本
…….val();
…….get(0).selectedIndex;

The above content is a detailed explanation of the usage of select in JS and jQuery introduced by the editor. I hope it will be helpful to everyone!