JSFiddle - React, Tailwind, and code Playground
HTML
<html>
<head>
<style>
input {
position: relative;
width: 90%;
}
</style>
<script>
function chng_div(src_id,div_id){
var src_obj = document.getElementById(src_id);
var div2chg = document.getElementById(div_id);
div2chg.style.width = src_obj.value+"px";
}
</script>
</head>
<body>
<select name="sizi_pixel" id="drp" onchange="chng_div('drp','div_to_chng');">
<option value="100">100 Pixels</option>
<option value="200">200 Pixels</option>
<option value="350">350 Pixels</option>
<option value="450">450 Pixels</option>
<option value="500">600 Pixels</option>
</select>
<div style="border-width:3px;border-style:solid;border-color:#ff9900; height:400px; width:300px" id="div_to_chng">
<input class="color" value="999">
<input class="color" value="999">
<input class="color" value="999">
</div>
</body>
</html>