如果$ _POST ['value']在数据库中，那么弹出警报的最佳方法是什么？

Question

I'm making a script where a user enters a value and clicks Submit. However, I want it to pop up an alert asking if they are sure, if the value is already in the database. I was thinking of doing this with AJAX, but a friend of mine is a jQuery fanatic and told me to go with that instead.

What would be better for this task, and how would I go about doing it in the respective choice? I found a tutorial on Tizag that explained how to do something similar, but they said that a submit button wasn't needed, and thus didn't include anything about it.

EDIT: Some code was requested, here it is:

if (isset($_POST['submit'])){
    $sql = "SELECT * FROM table WHERE column='$data'";
    $query = mysql_query($sql) or die(mysql_error());
    $number = mysql_num_rows($query);
    if ($number > 0){
        //needs to pop up
        //if user selects yes {
            //continue
        //}else{
            //break
        //}
    }
}

Something along these lines, although I know I need to start the AJAX prior to this code or it will have to reload the page.

Answer 1

Ajax is something you can implement with either vanilla javascript or with jQuery, the jQuery makes it really easy though.

Have a look at:

jQuery Ajax Tutorial