Several objectives in HTML5 are different from that of HTML4. The former one is defined error handling and it is consistent. HTML supports the ability to write malformed code or tag soup. The major problem is that the rules to write these codes aren’t mentioned anywhere. When a new browser enters the market, it must check the malformed documents in different browser. If it didn’t then several pages may not be displayed correctly. HTML5 is trying to identify and codify this error handling, so that the particular browser developers can reduce the time and money for providing quality display. Document format in HTML has died long back, but still many historians need to read our documents, and fully defined parsing algorithm has more value.