HTML5 banners have to be sent 2 full work days before live. If due date is not followed then Delfi Meedia cannot guarantee material activation. In that case compensation is not granted.

Technical specifications for HTML5 creatives

Single Zip

Creative should be sent in a single zip file that contains the static HTML and all of the resources required (the creative should not include resources from 3rd party sites unless stated otherwise).


Creative weight (total file size) should not exceed the allowed weight limit of the placement.
Banner weight is calculated as unZIPed.
The core libraries of the more popular media creation tools should not be included in the zip and will not be counted towards the weight limit of the banner. For example Adobe Animate CC, Adobe Edge, Google Web Designer, Tumult Hype, etc.


We do not support MRAID banners and those should be converted to Display Standard banners.


Special effects should be used reasonably (respect user experience and hardware load).


Creative must work in all modern browsers (oldest supported browser are IE10, Chrome 20, Firefox 20)


If you want to use a 3rd party viewtracker, then send it with the creative. Don't inject trackers to the creative code.


With the number of different sreen size in the market growing rapidly we require the banners, we show on mobile devices, to be responsive. Please follow he below link for instructions on how to create responsive banners with most popular creation tools.
How to make a responsive HTML5 banner


All banners require https compliance. This means that the banner cannot make any requests to unsecure domains. All request must be to https.
How to make HTTPS compliant banners


Delfi Meedia uses AdForm clicktag implementation.

Add the Adform.DHTML.js library to the head section of the banner:

    document.write('<script src="'+ (window.API_URL || ''+ Math.random()) +'"><\/script>');

That defines the dhtml variable that can be used as follows:'clickTAG', ''), '_blank');
Where dhtml.getVar('clickTAG') will fetch the clickTAG URL and will open that URL in a new window.
Note that '' is NOT the final destination URL but for local testing only.

» Detailed instructions on how to add clickTAG

Good Practices
For best user experience and page performance plese keep in mind the following best bractices:

  • Make your creative light - Your banner should load as fast as possible.
  • Only use assets you need - Delete all unused assets (fonts, grapchics etc)
  • Optimize your raster images (jpg, png, gif)
    • Avoiding narrow lines and small text - image compressing will make them blurry. You can add small lines and text in HTML
    • Save images web optimized, without any metadata
    • After saving jpg/png files - optimize your images also with image optimizers like (NB! use lossless option)
  • Using Custom fonts
    • Custom fonts should also have always fallback to a web-safe font (Arial, etc). NB! Do not forget to test your fallback font.
    • Fonts should be provided by Google fonts or included inside of the zip file with rest of the creative resources.
    • If you are using Adobe Edge the default fonts are recommended - they have websafe font fallback defined for them.
  • WebGL - WebGL is special case and not allowed by default. Please contact us before you use them

Different ad creation tools

Below we have compiled a list of specification pages for most common tools that are used to create html5 banner ads.

Below we have compiled a list of different instructional pages for most common issues and their possible solutions.