JavaScript获取下拉列表所有选项值的方法

<!DOCTYPE html>
<html>
<head>
<script>
function getOptions()
{
var x=document.getElementById("mySelect");
var txt="All options: ";
var i;
for (i=0;i<x.length;i++)
 {
 txt=txt + "\n" + x.options[i].text;
 }
alert(txt);
}
</script>
</head>
<body>
<form>
Select your favorite fruit:
<select id="mySelect">
 <option>Apple</option>
 <option>Orange</option>
 <option>Pineapple</option>
 <option>Banana</option>
</select>
<br><br>
<input type="button" onclick="getOptions()"
value="Output all options">
</form>
</body>
</html>