Question

How to make up a form that is going to be a search box and work only via Ajax? That is:

1) What to put as the form’s action value? (action=”what”)

2) How to submit it so that nothing else happenes except for calling the JavaScript function?

Answer 1

You can do something like:

<input id="search" /> <input type="button" onclick="doSearch()" />
<div id="results"></div>

dosearch will be something like

function doSearch()
    {
    var s = document.getElementById("search");
    // Substitute this line with whatever code you use to do an AJAX call
    // Essentially call a serverside page by passing the search keyword and
    // call onReturn afterwards 
    doAJAXCall("searchpage.php?q="+s.value, onReturn);
    }

searchpage.php will search the DB as needed and then return, for instance, a JSON string (e.g. by storing the results in an array and using json_encode) or XML or even straight HTML

Finally, the onReturn function will go through the results and print them for instance in a list, like this:

 function onReturn(results)
     {
     // decode your results variable here in the appropriate way
     // e.g. into a JSON object 
     var d = document.getElementById("results");

     var res = "<ul>";

     for (var i=0; i<results.lenght; i++)
         res = res + "<li>"+i.text+"</li>";

     res = res + "</li>";
     d.innerHTML = res; 
     }