Ajax，PHP，Javascript，智能解决方案

Question

I am currently creating a type of "classifieds" website, and when the user enters the site he/she is able to choose for example "Vehicles" in a dropdown list, and then choose mileage, year, price range etc...

Here is my problem, I have managed to make contact with a db using Ajax to call a php script which then checks the mysql db for the search criteria and returns a result. BUT, I need to make this as "smart" as possible...

How can i make a function or maybe a loop to check what category the user chose, and then to see if the user made any specifications on price or mileage for example, and then build a query_string to send to the php code, which then checks the mysql database for the search?

Heres a bit of code from the Ajax file:

//Browser Support Code
function ajaxFunction(){
var ajaxRequest;  // The variable that makes Ajax possible!

try{
    // Opera 8.0+, Firefox, Safari
    ajaxRequest = new XMLHttpRequest();
} catch (e){
    // Internet Explorer Browsers
    try{
        ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
        try{
            ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e){
            // Something went wrong
            alert("Your browser broke!");
            return false;
        }
    }
}
// Create a function that will receive data sent from the server
ajaxRequest.onreadystatechange = function(){
    if(ajaxRequest.readyState == 4){
        var ajaxDisplay = document.getElementById('cont');
        ajaxDisplay.innerHTML = ajaxRequest.responseText;
    }
}       

var category = document.getElementById('nav_category_list').value;
var city = document.getElementById('nav_city_list').value;
var querystring = document.getElementById('nav_querystring').value;
var cars_price_from = document.getElementById('cars_price_from').value;
var cars_price_to = document.getElementById('cars_price_to').value;
var cars_year_from = document.getElementById('cars_yr_from').value;
var cars_year_to = document.getElementById('cars_yr_to').value;
var cars_mileage_from = document.getElementById('cars_mile_from').value;
var cars_mileage_to = document.getElementById('cars_mile_to').value;
var cars_grbx = document.getElementById('cars_grbx').value;
var cars_fuel = document.getElementById('cars_fuel').value;

var send_query = "?category=" + category + "&city=" + city + "&cars_price_from=" + cars_price_from + "&cars_price_to=" + cars_price_to + "&cars_year_from=" + cars_year_from + "&cars_year_to=" + cars_year_to + "&cars_mileage_from=" + cars_mileage_from + "&cars_mileage_to=" + cars_mileage_to + "&cars_grbx=" + cars_grbx + "&cars_fuel=" + cars_fuel +"&querystring=" + querystring;

ajaxRequest.open("GET", "bincgi/ajax-example.php" + send_query, true);
ajaxRequest.send(null); 
}

Edited to add:

I don't have time to learn jQuery. I am sorry guys, but could you just point me in the right direction when it comes to the coding of this…

What would be the "best" way for doing what I want?

Also, there is an error if all elements in the array that I send to the php file isn't filled with values... If an array is empty, then the script will crash...

Any suggestions on how to solve this easily?

Answer 1

Why not just add the item->value to an array (using jQuery) upon user selection, and pass this array to the php?

The in the PHP explode the array and check each element?