获取JavaScript中组合框的选定索引的值

Question

i am trying to get the value of the selected index in my javascript

here i am defining my list box

<select name="combo" id="combo"  OnBlur="retrieveData(this.form)" ></select>

here i am trying to get the value (inside the form)

    alert(form.combo.value); // NOT working
    alert(form.combo.selectedIndex)  // working
    alert(form.combo.selectedIndex.value)  // NOT working

but its showing "undefined"

Answer 1

form.combo.options[form.combo.selectedIndex].value;

Answer 2

try this: in your html:

<select name="combo" id="combo" OnBlur="getComboVal(this)" ></select>

in javascript:

function getComboVal(sel)
{
    alert (sel.options[sel.selectedIndex].value);
}