Question

i come today to show an error thrown by opera in Jquery ,about object transformation , here is the code ( function setColor(x,y) ):

colourpixel = $('#colour').css('background-color').match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);//["rgb(0, 70, 255", "0", "70", "255"]

var canvas = document.createElement('canvas');
canvas.height=190;
canvas.width=190;
canvascontext = canvas.getContext("2d");
defaultdata = $('#light').get(0).getContext("2d").getImageData(0,0,190,190);
canvascontext.putImageData(defaultdata,0,0);

canvascontext.globalCompositeOperation = 'destination-atop';
canvascontext.fillStyle='rgb( '+colourpixel[1]+', '+colourpixel[2]+', '+colourpixel[3]+')';

And here is the error thrown by opera :

Uncaught exception: TypeError: Cannot convert 'colourpixel' to object  
Error thrown at line 157, column 1 in setColor(x, y) in   file://localhost/home/angelus/Desarrollo/webs/ColorP/functions.js:  
    canvascontext.fillStyle='rgb( '+colourpixel[1]+', '+colourpixel[2]+',   '+colourpixel[3]+')';
called from line 61, column 2 in <anonymous function>(event) in file://localhost/home/angelus/Desarrollo/webs/ColorP/functions.js:
    setColor(x,y);
called from line 55, column 294 in <anonymous function: handle>(a) in file://localhost/home/angelus/Desarrollo/webs/ColorP/jquery.min.js:
    i=i.handler.apply(this,arguments);
called via Function.prototype.apply() from line 49, column 569 in <anonymous function: o>() in file://localhost/home/angelus/Desarrollo/webs/ColorP/jquery.min.js:
    return typeof c!=="undefined"&&!c.event.triggered?c.event.handle.apply(o.elem,arguments):w

I have tried to create the object like an array ( var colourpixel = new Array(); ) but nothing run.

Thank you in advance!

Answer 1

I’m not sure the best fix since I don’t deal with this color situation at all, but here’s that the problem is:

In opera when you set a style as rgb(...), for example:

<div id="colour" style="background-color: rgb(0, 70, 255);">​

In most browser’s for $('#colour').css('background-color') you’ll get: "rgb(0, 70, 255)", but that’s not true in Opera, you’ll get a hex format of "#0046ff", so your regex won’t match and colourpixel will be null, not an array of matches. This causes your errors, the same as null[1] would.

Here’s a quick test to demonstrate this, test it in any other major browser, then Opera.