Question

I am trying to create a JS function that will take a value from a dropdownlist, add it as a query string to a http link and then open that link.
How to go about that?

Let’s say this is the <select>

<select>
   <option value="volvo">Volvo</option>
   <option value="saab">Saab</option>
   <option value="mercedes">Mercedes</option>
   <option value="audi">Audi</option>
 </select> 

How would I use that in DOM to access the value of the selected item on the DDL?

function openlink(link) {
            window.open(link + "SELECTED_ITEM_GOES_HERE");
        }

What is the syntax for SELECTED_ITEM_GOES_HERE?

Answer 1

You need this:
Get selected value in dropdown list using JavaScript?

And this:
How to set querystring with Javascript

To produce this:

<select id="test">
   <option>Volvo</option>
   <option>Saab</option>
   <option>Mercedes</option>
   <option>Audi</option>
</select>

<script>
var ddl = document.getElementById('test');
ddl.onchange = function(){
    window.location = 'https://www.google.com.au/search?hl=en&q=' + ddl.options[ddl.selectedIndex].text;
};
</script>