JSFiddle - React, Tailwind, and code Playground

HTML

<form name="myForm" method="post" action="http://google.com" id="myForm"  >

    <select name="modeOfT" id="choice">
        <option value="A">A</option>
        <option value="B">B</option>
    </select> 

    <input type="submit" name="submitBtn"/>
</form >

JavaScript

$('#myForm').submit(function(e){
    if ( $('#choice').val() === 'B') {
        this.action = 'http://msn.com';
    }
});