You can cancel the form submission by registering a submit event handler and prevent the default behavior if one of your fields is empty:
$("form").submit(function(event) {
if ($("input:text[name='member_name\\[\\]'][value='']", this).length) {
window.alert("No member name should be empty.");
event.preventDefault();
}
});
EDIT: As naveen correctly points out, the code above would still submit the form if the fields only contain whitespace. You can use $.trim() with filter() to fix the problem:
$("form").submit(function(event) {
if ($("input:text[name='member_name\\[\\]']", this).filter(function() {
return $.trim(this.value) == "";
}).length) {
window.alert("No member name should be empty.");
event.preventDefault();
}
});