How to set default value for HTML select? [duplicate]

You first need to add values to your select options and for easy targetting give the select itself an id.

Let’s make option b the default:

<select id="mySelect">
    <option>a</option>
    <option selected="selected">b</option>
    <option>c</option>
</select>

Now you can change the default selected value with JavaScript like this:

<script>
var temp = "a";
var mySelect = document.getElementById('mySelect');

for(var i, j = 0; i = mySelect.options[j]; j++) {
    if(i.value == temp) {
        mySelect.selectedIndex = j;
        break;
    }
}
</script>

Also we can use “text” property of i to validate:

if(i.text == temp)

See it in action on codepen.