Modern.ie: suggest a fix or enhancement with web standards like HTML5 & CSS3.

Despite the fact that it’s not a complete checklist for coding the modern web, Microsoft via this project aims to help developers to detect common coding practices that may cause compatibility problems. And also help users from getting the best possible experience on a webpage.

Besides Modern.IE when it is possible can suggest a fix or enhancement with web standards like HTML5 & CSS3. 
In fact the goal here is to ‘’spend less time testing for the various versions of Internet Explorer ''
According to Microsoft, what is true, there are still a lot of users that browse with older versions of Internet Explorer. Therefore, modern.IE aims to be a way to help move the web forward by making it easier to build innovative experiences with web standards like HTML5 & CSS3 while supporting older versions of IE.
In regards to the code detection wizard, modern.IE aims to scan your code without executing the code itself and reports the webpage results in three categories:
1.    Address common problems that result from supporting older versions of IE.
2.    Help the site work well across browsers, across devices.
3.    Consider building with some new features in Windows 8.
Modern.IE also includes free access to BrowserStack, a virtual browser testing site that lets developers test their site on any browser available on Windows. Without forgot  add-ins for Chrome or Firefox, which give you access to the BrowserStack virtual testing service right from your browser of choice.
However this offer is available for three months of free service .