AJAX / jQuery：根据数值改变DIV背景？

Question

I am new with AJAX/jQuery and trying something new.

here is my fiddle for better understanding Each of those squares are DIVS.

<div class="desk_box_ver" id="desk_B20" data-rel="85" style="left:20px;top:1165px;">B20</div>

The number inside of is being retrieved with an AJAX call that GETs it with a PHP script executing a query, it will replace the "B20" for "1300" as an example.

Problem:

How can I produce a "heat map" based on the numbers being displayed. Example: Lets say the number range is from 100(the lowest) to 1800(the highest). Depending on the number range, a background color will have to be displayed from green-ish, to yellow-ish, orange-ish, and red.

A similar problem I found on stackoverflow is this one

AJAX:how I am displaying the numbers inside of the DIVs

<script type="text/javascript">
            $(document).ready(function() {
                $('#aht').click(function(){
                    $.ajax({
                    type:"GET",
                    url : "show_aht.php",
                    data:{  } , // do I need to pass data if im GET ting?
                    dataType: 'json',
                    success : function(data){
                        //going through all DIVs only once with this loop
                            for(var i = 0; i < data.length; i++) { // loop over results
                            var divForResult = $('#desk_' + data[i]['station']); // look for div for this object
                            if(divForResult.length) { // if a div was found

THIS IS WHERE I AM OUTPUTTING THE NUMBER

      divForResult.html(data[i]['aht_value']); // set inner HTML with AHT value


                            }//end if
                            }//end for
                      }//end success
                });//end ajax
              });//end click
            });//end rdy
        </script>

show_aht.php numbers being retrieved from the array below

$result = array();
    foreach ($memo as $username => $memodata) {
    if (in_array($username, array_keys($user))) {
    // Match username against the keys of $user (the usernames) 
    $userdata = $user[$username];
    //if AHT is null give N/A as value
    if (is_null($memodata['aht_value'])) {
        $result[] = array( 'username'  => $userdata['username'],
                                             'aht_value' => 'NA',
                                             'station'  => $userdata['station']
                                            );
    }//end inner if 
    //else give the actual value of AHT without the decimals
    else {
        $result[] = array( 'username'  => $userdata['username'],
                                             'aht_value' => substr($memodata['aht_value'],0,-3),
                                             'station'   => $userdata['station']
                                            );
    }//end else
    }//end outer if
    }//end for

echo json_encode($result);

Answer 1

Have a play with this fiddle. It inserts a value and then applies a color to is (using a very simple algorithm that you will want to change). Here's how you could implement it in your code

success : function(data){
  for(var i = 0; i < data.length; i++) { // loop over results
    var divForResult = $('#desk_' + data[i]['station']); // look for div for this object
    if(divForResult.length) { // if a div was found
       divForResult.html(data[i]['aht_value']).css("background-color", colorMe(data[i]['aht_value']));
    }//end if
  }//end for
}//end success

Make these available in your code:

function colorMe(v){
    return "rgb(" + conv(v) + "," + (255-conv(v)) + ",0)";
}

function conv(x){
    return Math.floor((x - 100) / (1800-100) * 255);
}