Wrong representation of php data with jqplot - php

Question

I have problems to create an array which is evaluated correctly by jqplot.
If i try it like this, i have an x-axis range from -5 to 95 but with the correct line.
Actually i would expect a chart with x-axis from 0 to 30.
With firebug i can check with typeof that params is an object (array).
Where is the failure?
Here is my getPlotData.php with some dummy data:
$temp = array();
for( $i=0; $i<30; $i++ ){
$temp[] = "[" . $i . "," . ($i*5) . "]";
}
$return['line'] = "[" . implode(',', $temp . "]";
die(json_encode($return));
And here is my ajax function which is calling the createPlot-function:
$.ajax({
type: "GET",
dataType: "json",
url: "getPlotData.php?rand=" + new Date(),
data: data,
cache: false,
success: function(data) {
var params = eval(data['line']);
createPlot(params);
}
});
function createPlot(params){
plot1 = $.jqplot('plot_data', [params], {
series:[{showMarker:true}],
markerOptions: { style:'circle' },
axesDefaults:{
tickRenderer: $.jqplot.CanvasAxisTickRenderer ,
tickOptions: {
fontSize: '14px',
textColor: "#fff"
}
},
axes:{
xaxis:{
labelRenderer: $.jqplot.CanvasAxisLabelRenderer,
label:'Tag',
tickOptions:{
},
labelOptions: {
fontSize: '13pt',
textColor: '#FFFFFF'
}
},
yaxis:{
label:'Anzahl',
labelRenderer: $.jqplot.CanvasAxisLabelRenderer,
tickOptions:{
},
labelOptions: {
fontSize: '13pt',
textColor: '#FFFFFF'
}
}
}
});

Answer 1

Currently you are using implode and json_encode. I guess, that manually creating JSON might produce some kind of error in the output. (Like double encoding the JSON data.)
It should work if you only add the data to the array first and then json_encode whole dataset.
<?php
$temp = array();
for( $i=0; $i < 30; $i++ ) {
$temp[] = array( $i, $i*5 );
}
$return['line'] = $temp;
die( json_encode( $return ) );