JavaScript validation required field border changed

/////////////////////////////////////////Just Copy Past///////////////////////////////

<form name= "reg" id="reg" method="POST" action="http://www.qualityzoneinfotech.com/" onsubmit="return validate()">

   
    <input id="first" name="first" type="text" value="" placeholder="first"><br />

<input id="email" name="email" type="text" value="" placeholder="email"><br />

<textarea id="message" name="message" placeholder="message" ></textarea><br />
    <input type="submit"></button>
</form>

<script type="text/javascript">

function validate(){
    var formIsValid = true;
    var first=document.forms["reg"]["first"];
    if(first.value == null || first.value == ""){
        first.style.borderColor = "red";
        formIsValid = false;  
    }
 var email=document.forms["reg"]["email"];
    if(email.value == null || email.value == ""){
        email.style.borderColor = "red";
        formIsValid = false;  
    }
 var message=document.forms["reg"]["message"];
    if(message.value == null || message.value == ""){
        message.style.borderColor = "red";
        formIsValid = false;  
    }

    return formIsValid;

}
</script>