$('button').click((e)=>{
	e.preventDefault();
	if($('select').val() === 'google'){
		let url = $('#search').val();
		console.log(`Text before: ${url}, selected: ${$('select').val()}`);
		url = `https://www.google.com/search?q=${url}&sourceid=chrome&ie=UTF-8`;
		window.open(url, '_blank'); // open in new tab
	}
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form>
    <select>
        <option value="google">Google</option>
    </select>
    <input size="50" type="search" id="search" name="q"></input>
	<button>search</button>
</form>