canvasOverlay show in jqplot - show

Question

How do I trigger on the overlays in jqplot only after I click a checkbox (not when the html loads). When I first set overlay option show to false the overlays are not displayed on plot at 1st and when I used my trigger function the overlays do not appear.
Here is the code I use for the plot :
<div id="fastest" style="margin-top:20px; margin-left:20px; margin-right:200px; width:800px; height:400px;">
<script class="code" type="text/javascript">
$(document).ready(function(){
var dataset="too long to be displayed here"
plot1 = $.jqplot('fastest', dataset, {
title: 'Test_figs',
legend: {show:false},
series: [{
showMarker: false,
color: '#ED0E0E',
label: 'R spectrum',
neighborThreshold: -1
}],
axes:{
xaxis:{
label:'Restframe Wavelength'
},
yaxis:{
label:'Flux',
tickOptions:{formatString:'%.3e'}
}
},
cursor:{
show:true,
zoom:true,
tooltipLocation:'sw'
},
Canvasoverlay: {
show: false,
objects: [
{verticalLine: {
name: 'Na-ID',
x: 5893.000000,
lineWidth: 2,
color: '#F0630C',
lineCap:'butt',
yOffset:0,
shadow: true
}}
]
}
});
});
function NaID_trigger() {
var co = plot1.plugins.canvasOverlay;
var line = co.get('Na-ID');
if (line.options.show==false) line.options.show = true;
else line.options.show = false;
co.draw(plot1);
}
</script>
I then use :
<button onclick="NaID_trigger()">Na-ID</button>
to trigger the overlay on or off for instance.
PS: I tried replacing draw by replot as advised didn't work when show=false in overlays options.

Answer 1

I finally found the solution myself :
to not display the overlays when the jqplot loads I set the overall overlays "show" option to true.
Then within each object I set show to false.
Instead of the external to the plot function I used before I switched to an even handler of the form:
$("input[type=checkbox][name=Na-ID]").change(function(){
plot1.plugins.canvasOverlay.get('Na-ID').options.show = this.checked;
plot1.replot();
});
Now the plot display the selected overlay when checkbox is ticked and not at the beginning.
Hope this will help someone who has the same issues.