Unlike Adobe, Microsoft seem to be understanding that HTML5 is the only true cross-platform solution:
When Microsoft first showed off Internet Explorer 9, its most HTML 5 compliant version of IE to date, in March of this year, questions began to arise about the company’s commitment to Silverlight. Officials insisted that the two would coexist and that Silverlight would be Microsoft’s cross-platform development platform for mobile, Web and PC platforms for a number of years to come, as HTML 5 was far from becoming an accepted standard.
But in the past few months, Microsoft’s backing of HTML 5 has gotten more aggressive. Microsoft is pushing HTML 5 as the way developers can make their Web sites look more like apps.
This is a smart move by Microsoft: they can continue to develop Silverlight as a development platform for Windows Phone, whilst encouraging developers to create cross-platform applications with HTMl5 – best of both worlds, and it won’t cost them anything.