Change Color on Entry into the TextBox

<input type="text" id="textBoxVal" />

document.getElementById("textBoxVal").focus();
document.getElementById("textBoxVal").style.backgroundColor = "lightsalmon";

$("#textBoxVal").keyup(function() {
 var inputVal = document.getElementById("textBoxVal").value;
        if (inputVal == "") {            document.getElementById("textBoxVal").style.backgroundColor = "lightsalmon";
        }
        else {
            document.getElementById("textBoxVal").style.backgroundColor = "white";
        }


});