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("Please enter a valid Email Address")
       return false
    }

    if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
       alert("Please enter a valid Email Address")
       return false
    }

    if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
        alert("Please enter a valid Email Address")
        return false
    }

     if (str.indexOf(at,(lat+1))!=-1){
        alert("Please enter a valid Email Address")
        return false
     }

     if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
        alert("Please enter a valid Email Address")
        return false
     }

     if (str.indexOf(dot,(lat+2))==-1){
        alert("Please enter a valid Email Address")
        return false
     }
    
     if (str.indexOf(" ")!=-1){
        alert("Please enter a valid Email Address")
        return false
     }

     return true                    
}


function checkValues() {
    if ( $("#name").val() == '' ) { return false; }
    if ( $("#email").val() == '' ) { return false; }
    if ( $("#day").val() == '' ) { return false; }
    if ( $("#month").val() == '' ) { return false; }
    if ( $("#year").val() == '' ) { return false; }
    return true;
}

function saveData() {
    $.ajax({ type: "POST", url: "backend.php", 
        data: "name="+$("#name").val()+"&"+
        "email="+$("#email").val()+"&"+
        "day="+$("#day").val()+"&"+
        "month="+$("#month").val()+"&"+
        "year="+$("#year").val(),
        success: function(msg) { alert("Your data has been saved, we will email you 4 weeks before your Interest Free Expiry Date"); },
        error: function(obj,msg) { 
            alert("There was a problem saving your data. Please Retry"); 
        }
    });
}

function checkClick() {
    fieldsOK = checkValues(); 
    if ( !fieldsOK ) {
        alert("You must enter all the details to continue!");
        return false;
    }
    if (echeck($("#email").val())==false){
        $("#email").val("");
        return false
    }
    
    saveData();
    return false;
}

// CONTROLLING EVENTS IN jQuery
$(document).ready( function() {
    // Click the button event!
    $("#submit").click( function() {
        // check the entered values
        checkClick()            
    });
});