Simple PHP/AJAX question - php

Question

Ok, so I am fairly new to webdeveloping, so probably a silly question:
I have this search form which does autocomplete for fooditems (gets values from a database column) and that works. Now when I press the submit button I want to load a block of code that displays the food-items' calories etc (also in the database on the same row as the food-item).
How can I accomplish such a thing. I kno this is a fairly broad question, but what i am really asking is, how can I make a small part of my website reload when pressing the submit button and using the input given in the text field as a parameter of some kind.
I don't need whole answers, just any tips getting to the right path would be greatly appreciated!
here my code for the input and button:
in head
<script type="text/javascript" src="jquery.js"></script>
<script>
function ok(){
$.post("test.php", { name: "John", time: "2pm" }, function(data){ alert("Data Loaded: " + data); });
}
</script>
in body:
<form autocomplete="off">
<p>
Food <label>:</label>
<input type="text" name="food" id="food" / >
</p>
<input type="submit" id="submit" value="Submit" onclick="ok()" />
</form>
or:
head:
<script type="text/javascript" src="http://code.jquery.com/jquery-1.4.4.js"></script>
<script>
$("input[type='submit']").bind("click", function (event) {
event.preventDefault(); // Stop a form from submitting
$.post("/path/to/call", { /* data? */ }, function (data) {
// Process return data here
});
});
</script>
body:
<form autocomplete="off">
<p>
Food <label>:</label>
<input type="text" name="food" id="food" / >
</p>
<input type="submit" id="submit" value="Submit" />
</form>

Answer 1

jQuery and Ajax.
Change that input to a button
<button id="submit">Save</button>
For this I would do something like:
$("button#submit]").bind("click", function (event) {
event.preventDefault(); // Stop a form from submitting
$.post("/path/to/call", { /* data? */ }, function (data) {
// Process return data here
});
});
You need to first catch the click event .bind("click"). Then initiate an ajax call $.post which you will send data to. This data is received on the server via the POST array.

Answer 2

Like Josh said, jQuery is the way to go here.
You'll want to do 3 things:
Attach a click handler to a button like "onclick='doSomething();'"
In that function,use jQuery to do an async post to a script like
$.post("test.php", { name: "John", time: "2pm" },
function(data){
alert("Data Loaded: " + data);
});
When this comes back, you can do something with that data(instead of the alert above), like $('#listnode').append... which would stick the HTML into your list
This is the general pattern, but you'll have to fit it to your scenario.

Answer 3

It is hard to answer your question from what little you have given us, but I will assume little knowledge.
Your input fields have to be inside a form tag. The form tag includes an action and a method. The method must be "POST" to send the data. The action can be any URL.
You simply have to name the URL of your php script that will handle the results.
It will find the data in $_POST['food'] etc. It has to build the reply page - the whole screen, with the food and data and the search form for the next submit if you want.
If you want to use AJAX to replace part of the screen, then you have a whole nother level of problems. The trick is to replace the content of a div tag with the requested data.