当用户点击提交时，如何在图表中显示计算结果？

I'm using http://canvasjs.com/ to create a bar graph. So far, when the user clicks 'submit' the entered numbers are displayed on a graph http://jsfiddle.net/jx9sJ/5/ .

Now, I'm trying to change it. So the entered numbers are sent to ajax, calculations done, & then encoded using json_encode($total); I'm struggling to create the graph from the values, which are in json_encode. How can this be done?

Code so far

$fortot2 = 5;
$fortot3 = 2;

if (is_numeric($numwelds) && is_numeric($numconwelds))
{
    $total['tot1'] = $numwelds + $numconwelds + $fortot3  ;
    $total['tot2'] = $numwelds + $numconwelds + $fortot2 ;
    $total['tot3'] = $numwelds + $numconwelds; 
    $response = json_encode($total);
    header("Content-Type: application/json");  
    echo $response;
    exit;
} 

Using print_r json_encode($total) is structured as

  Array ( [tot1] => 3 [tot2] => 5 [tot3] => 1 ) 

First of all,

Array ( [tot1] => 3 [tot2] => 5 [tot3] => 1 ) 

is not json_encoded and rather looks like var_dump( $total ).

Then you have to populate the data object that is used on line 15 of your JSFiddle with the values from JSON, which requires some basic knowledge of AJAX. I suggest that you first familiarize yourself with that.