Unicode and HTML with detectable errors. Currently, Gecko browsers such as Firefox, abide to this rule, whereas the bulk of the other common browsers that support HTML as XML, such as Webkit browsers (Chrome/Safari) do allow the encoding of XHTML documents to be manually overridden. Many browsers are only capable of displaying a small subset of the full Unicode repertoire. Here is how your browser displays various Unicode code points: Some web browsers, such as Mozilla Firefox, Opera, Safari and Internet Explorer (from version 7 on), are able to display multilingual web pages by intelligently choosing a font to display each individual character
Upload components for uploading files are still not part of the standard, HTML5 upload components are not common at the moment. Their support is restricted to a subset of browsers. HTML5 support has been steadily improving. The best coverage of HTML5 features is provided by the latest version of Chrome, Firefox, Safari and Opera. Internet Explorer provides the least support. Internet Explorer 10 has less support than versions of other browsers; however the coverage will be twice as good as Internet Explorer 9. iOS 5 has a sufficiently high level of HTML5 support; however, its level of support remains lower than for