js动态添加,删除option及add的使用方法
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>动态建立select及option及add的使用</title>
</head>
<body>
</body>
<script type="text/javascript">
//1.创建select
function createSelect(){
var mySelect = document.createElement("select");
mySelect.id = "mySelect";
document.body.appendChild(mySelect);
}
createSelect();
//2.创建option
function addOption(){
//根据id查找对象，
var obj=document.getElementById('mySelect');
//添加一个选项
//方法一：
obj.add(new Option("文本text1","value值"));
//或方法二：
obj.options.add(new Option("文本text2","value值"));
}
addOption();
// 3.删除所有选项option
function removeAll(){
var obj=document.getElementById('mySelect');
obj.options.length=0;
}
// removeAll();
// 4.删除一个选项option
function removeOne(){
var obj=document.getElementById('mySelect');
//index,要删除选项的序号，这里取当前选中选项的序号
var index=obj.selectedIndex;
console.log(index)
obj.options.remove(index);
}
removeOne();
// 5.获得选项option的值
var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val = obj.options[index].value;
console.log(val)
// 6.获得选项option的文本
var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val2 = obj.options[index].text;
// 7.7.修改选项option
var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val3 = obj.options[index]=new Option("新文本","新值");
// 8.删除select
function removeSelect(){
var mySelect = document.getElementById("mySelect");
mySelect.parentNode.removeChild(mySelect);
}
</script>
</html>
