diff options
| -rw-r--r-- | js/reveal.js | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/js/reveal.js b/js/reveal.js index 473a616..b975ff4 100644 --- a/js/reveal.js +++ b/js/reveal.js @@ -855,15 +855,15 @@ // If this slide has a background color, add a class that // signals if it is light or dark. If the slide has no background // color, no class will be set - var computedBackgroundColor = window.getComputedStyle( element ).backgroundColor; - if( computedBackgroundColor ) { - var rgb = colorToRgb( computedBackgroundColor ); + var computedBackgroundStyle = window.getComputedStyle( element ); + if( computedBackgroundStyle && computedBackgroundStyle.backgroundColor ) { + var rgb = colorToRgb( computedBackgroundStyle.backgroundColor ); // Ignore fully transparent backgrounds. Some browsers return // rgba(0,0,0,0) when reading the computed background color of // an element with no background if( rgb && rgb.a !== 0 ) { - if( colorBrightness( computedBackgroundColor ) < 128 ) { + if( colorBrightness( computedBackgroundStyle.backgroundColor ) < 128 ) { slide.classList.add( 'has-dark-background' ); } else { |