E_K

<input type="text" size="40" id="search" onkeyup="searchVal()">

<script>
function searchVal(){
  console.log(search.value);
  var xhr = new XMLHttpRequest();
  xhr.open('GET', './php/sql.php?input='+document.getElementById("search").value, true);
  if(xhr.status != 200){
    console.log( xhr.status + ': ' + xhr.statusText );
  }else{
    console.log(xhr.responseText );
  }
  xhr.send();
};
</script>