Javascript Error on Chrome - Solution

[zempa]

The error appears on the last release of Google Chrome (13) :
Line 791 : Uncaught TypeError: Cannot read property 'length' of null

So i try to redefine this length property.
Here is my solution :

- line 455 : add "+2" in the height of the canvas element.
  replace
  canvas.height = Math.round(this.pixelsFromPoints(face, style, face.lineHeight));
  by
  canvas.height = Math.round(this.pixelsFromPoints(face, style, face.lineHeight))+2;

- line 790 : add the following line between line 790 and line 791
  var lengthStyleSheet = (styleSheet.cssRules)? styleSheet.cssRules.length : 0;

- line 791 : change the last parameter in the insertRule function
  replace
  document.styleSheets[0].insertRule(typefaceSelectors.join(',') + ' { visibility: hidden; }', styleSheet.cssRules.length);
  by
  document.styleSheets[0].insertRule(typefaceSelectors.join(',') + ' { visibility: hidden; }',lengthStyleSheet );

- lines 801 and 826 : change the same parameter
  replace
  styleSheet.cssRules.length
  by
  lengthStyleSheet

The patched script in the attachment