下面的代码可以获得select option当前选中的值, 例如当我选中value=16的option, 就弹出16; <SCRIPT language="javascript" >
function showSelected()
{
var f = document.getElementById("age");
var i = f.options.selectedIndex;
alert(f.options[i].value);
}
</SCRIPT > <SELECT id="age" name="age" onchange="showSelected();" >
<OPTION value=16 >16Years </OPTION >
<OPTION value=18 selected>18Years </OPTION >
<OPTION value=20 >20Years </OPTION >
</select > 现在我想要的是option被改变前的值, 例如: 这个selection option最初selected的值是value=18, 当我把它选为value=16时,我怎么知道这个select otion的selected值在被改变前是value=18这一项?
function showSelected()
{
var f = document.getElementById("age");
var i = f.options.selectedIndex;
alert(f.options[i].value);
}
</SCRIPT > <SELECT id="age" name="age" onchange="showSelected();" >
<OPTION value=16 >16Years </OPTION >
<OPTION value=18 selected>18Years </OPTION >
<OPTION value=20 >20Years </OPTION >
</select > 现在我想要的是option被改变前的值, 例如: 这个selection option最初selected的值是value=18, 当我把它选为value=16时,我怎么知道这个select otion的selected值在被改变前是value=18这一项?
select每改变一次,全局变量的值都跟着改变
<SCRIPT language="javascript" >
function showSelected()
{
var f = document.getElementById("age");
var i = f.options.selectedIndex;
alert("之前:" + cur);
alert("现在:" + f.options[i].value);
cur = f.options[i].value;
}
var cur;
window.onload=function(){
var f = document.getElementById("age");
cur = f.options[f.selectedIndex].value;
}
</SCRIPT> <SELECT id="age" name="age" onchange="showSelected();">
<OPTION value=16 >16Years </OPTION>
<OPTION value=18 selected>18Years </OPTION >
<OPTION value=20 >20Years </OPTION>
</select>