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("The email address you entered is invalid. Please re-enter your email address.");
       return false;
    }

    if (str.indexOf(at) == -1 || str.indexOf(at) == 0 || str.indexOf(at) == lstr) {
       alert("The email address you entered is invalid. Please re-enter your email address.");
       return false;
    }

    if (str.indexOf(dot) == -1 || str.indexOf(dot) == 0 || str.indexOf(dot) == lstr) {
        alert("The email address you entered is invalid. Please re-enter your email address.");
        return false;
    }

    if (str.indexOf(at,(lat+1)) != -1) {
        alert("The email address you entered is invalid. Please re-enter your email address.");
        return false;
    }

    if (str.substring(lat-1,lat) == dot || str.substring(lat + 1, lat + 2) == dot) {
        alert("The email address you entered is invalid. Please re-enter your email address.");
        return false;
    }

    if (str.indexOf(dot, (lat + 2)) == -1) {
        alert("The email address you entered is invalid. Please re-enter your email address.");
        return false;
    }

    if (str.indexOf(" ") != -1) {
        alert("The email address you entered is invalid. Please re-enter your email address.");
        return false;
    }

    return true;
}


function validateForm(){

    // Fields
	var text_name=document.getElementById('text_name');
    var text_email=document.getElementById('text_email');
    var textarea_message=document.getElementById('textarea_message');
    
    // Checks
	if ((text_name.value == null) || (text_name.value == "")) {
		alert("Please enter your name");
		text_name.focus();
		return false;
	}

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

	if (echeck(text_email.value) == false){
		text_email.value = "";
		text_email.focus();
		return false;
	}

    if ((textarea_message.value == null) || (textarea_message.value == "")) {
		alert("Please enter a message");
		textarea_message.focus();
		return false;
	}
    
	return true;
 }