​x
 
<!DOCTYPE html>
<html>
​
<head>
<title>JS tutorial</title>
<style type="text/css">
body {
    margin:3px 10px; padding:3px;
    background-color:#345; color:#aaa;
    font-family:"Arial", serif;
}
input {
    font-size:0.8em; color:#555; margin:4px 0px 5px;
}
#res {
    padding:3px 4px; border:1px solid gray; color:#888; 
}
</style>
<script type="text/javascript">
    function clearField(field) {
        field.value = "";
    }
    function validateField(field, text) { 
        // letters
        if (text == "name") { 
            var pattern = new RegExp("^([A-z]{1,})+$"); 
            if (pattern.test(field.value)) {
                field.style.outline = "3px ridge green";
            }
            else { 
                field.style.outline = "3px ridge red";
            }
        }
        // numbers
        else if (text == "age") {
            var pattern = new RegExp("^([0-9]{1,})+$");