The html5shiv is the defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer. This project allows to use this library in Seaside.

See https://github.com/afarkas/html5shiv

Usage

You need at least "Seaside-Core-TorstenBergmann.833" (which adds #ie9 method) or later in Seaside and then you can write for older IE support:

 updateRoot: anHtmlRoot 
   "Updates the given HTML root object."
   super updateRoot: anHtmlRoot.
   anHtmlRoot title: 'My HTML5 app'.
   anHtmlRoot meta 
        name: 'viewport';
        content: 'width=device-width, initial-scale=1.0'.

   anHtmlRoot if lessThan; ie9; do: [
    HTML5ShivDeploymentFileLibrary default updateRoot: anHtmlRoot ]