2. Omission

2.0 Remove HTML comments

2.1 Remove whitespace

2.2 Remove unnecessary element attributes

2.2.0 Remove ALT tags from invisible images

2.2.1 Remove default attributes

2.2.2 Replace inline attributes with external styles

2.3 Remove quotation marks from element attributes

2.4 Omit Closing Tags

2.5 Serve META tags only to robots

2.6 Fix or Remove Broken Images

2.7 Use Assets on Demand

2.7.0 Javascript on Demand

2.7.1 CSS on Demand