$(document).ready(function() {
    $('input[type="text"], textarea').focus(function(){
        if (this.value == this.defaultValue) {
            this.value = '';
        }
    }).blur(function(){
        if (this.value == '') {
            this.value = this.defaultValue;
        }
    });

    $('form#contactForm').submit(function(){
        var field = $('#fieldAddress')[0];
        if (field.value.length == 0 || field.value == field.defaultValue) {
            $('#fieldAddress').addClass('error').focus()  ;
            return false;
        }
        var field = $('#fieldPostcode')[0];
        if (field.value.length == 0 || field.value == field.defaultValue) {
            $('#fieldPostcode').addClass('error').focus()  ;
            return false;
        }
        

        return true;
    });
});