I've done branding many times before but a new issue popped up today. I use Muse to design my sites, but today when I converted the master page from html to a SharePoint master page I got a
SharePoint requires HTML files to be XML-compliant. Your file isn't XML-compliant, likely because of tag properties without quotes, missing closing tags, or invalid properties in tags. 'data-main' is an unexpected token. The expected token is '='. Line 603, position 80. Occurred at: 2/8/2017 2:10:12 PM Run the file through an XML validator, fix any issues using your HTML editor, save the file, and refresh this preview.
When I take out the line
It shows up just fine but the java that makes the menus drop down stops working.