function checkform ( form )
{

if (form.name.value == "") {
    alert( "Please enter your name." );
    form.name.focus();
    return false ;
}

function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		   form.email.focus();
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		   form.email.focus();
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		    form.email.focus();
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		    form.email.focus();
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		    form.email.focus();
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		    form.email.focus();
		    return false
		 }

		 if (str.indexOf(" ")!=-1){
		    alert("Invalid email address.\r\n\r\ne.g. you@domain.com")
		    form.email.focus();
		    return false
		 }

 		 return true
	}

	var email=document.form.email

	if ((email.value==null)||(email.value=="")){
		alert("Please enter your email address")
		form.email.focus();
		return false ;
	}
	if (echeck(email.value)==false){
                form.email.focus();
		return false ;
	}

if (form.subject.value == "") {
    alert( "Please enter the subject of your enquiry." );
    form.subject.focus();
    return false ;
}

if (form.message.value == "") {
    alert( "Please enter your message." );
    form.message.focus();
    return false ;
}

  return true ;
}