Site redirect form select form

Demo

HMTL

<select id="select-id">
  <option value="" selected="">Pick a E-commerce</option>
  <option value="http://www.amazon.com">Amazon</option>
  <option value="http://www.flipkart.com">Flipkart</option>
  <option value="http://www.snapdeal.com">Snapdeal</option>
</select>
<button onclick="siteRedirect()">GO</button>

PHP

// Site redirect
add_action( 'wp_footer', 'chuyen_huong' );
function chuyen_huong(){
?>
<script>
  function siteRedirect() {
    var selectbox = document.getElementById("select-id");
    var selectedValue = selectbox.options[selectbox.selectedIndex].value;
    window.location.href = selectedValue;
  }
</script>
<?php
}