A Comparison Between HTML5 & Flash

What are the main differences between HTML5 & Flash? When HTML5 was initially created, it entered into a market that was dominated by Flash. Even after HTML5 was introduced, Flash was still the preferred option for many developers. However, today the landscape of the market has changed and in 2020 developers have transitioned from Flash almost entirely. So why are developers migrating to flash, this guide provides a head-to-head comparison!

Size Comparison 

HTML5 ads are larger in file size than Flash based ads. This is because HTML5 ads include the backup images, click tags/codes and other elements. Flash ads sizing, however, is based on the creative size only. Because of this, HTML5 ads are around 100Kb larger.

Lets talk money 

Constructing Flash ads can be costly. You have to create a Flash ad for every possible size placement. Once you create an HTML5 ad, the ad is responsive to all possible sizes.

Convenience & ease 

Flash has mature features, is familiar to developers, adopted by the vast majority of legacy browsers. Unlike Flash, which requires a dedicated plug-in, HTML5 can render multimedia content easily without plugins or player applications. However, the downside to this is that some older browsers do not support HTML5.

Picture clarity 

Flash has greater image clarity, as it can offer sub-pixel support. This results in crisper images. HTML5 can lead to inconsistency and unreliability in display.

Mobile support 

HTML5 offers better support for mobile sites. Flash is PC-based only, giving HTML5 a large advantage over Flash as we move into an era of mobile web accessibility. HTML5 offers much better cross device support.

Development resources 

Flash has a large resource pool and even larger community, whereas its counterpart is still a fairly new technology with a building community and some still prevalent inconsistencies and support issues.

Parent company 

Flash is not an open standard; it is controlled by ADOBE systems. Meanwhile, HTML5 is largely controlled by the Web Hypertext Application Technology Working Group (WHATWG) managed by – Mozilla, Opera Software and Apple.


Flash provides automatic optimization and compiles everything into a single compact file. While currently, the alternative offers no optimization. However, HTML5 ads can be packaged and delivered optimally as long as special attention is paid to their packaging.


HTML5 requires considerably lower processing power than Flash. This is partly due to more people using mobile devices.

Semantic elements 

In HTML5 semantic elements follow the HTML language use of the semantic/meaning of the information in webpages and web applications. This is an improvement of the use of non-semantic elements i.e. <div>, <span>, etc. to define web presentation. This results in faster processing. Flash does not provide this level of semantic functionality, and so does not benefit from the resulting performance improvements.

Bidding farewell to Flash

Flash is no longer the dominant force it once was. HTML5 is overcoming all short-comings like security and speed offered by Flash.

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