html - how to get custom attribute of option tag in dropdown?

Answer 1

You use: .getAttribute('isred')

You want:

<select onchange="alert(this.options[this.selectedIndex].getAttribute('isred'));" name="myname" class="myclass">
    <option isred="-1" value="hi">click</option>
    <option isred="-1" value="ho">click</option>
</select>