Case insensitive $.removeAttr implementation. Based off jQuery 1.7.1.

$.removeAttrI

(function($) {
  var rcaps = /[A-Z]/,
      rspace = /\s+/,
      rboolean = /^(?:autofocus|autoplay|async|checked|controls|defer|disabled|hidden|loop|multiple|open|readonly|required|scoped|selected)$/i;

  jQuery.fn.removeAttrI = function(value) {
    return this.each(function() {
      // Call normal `removeAttr`
      if (! value.match(rcaps)) {
        $(this).removeAttr(value);
      }
      // else: reimplement jQuery.removeAttr
      var propName, attrNames, name, l,
      i = 0,
      elem = this;

      if ( value && this.nodeType === 1 ) {
        attrNames = value.split( rspace );
        l = attrNames.length;

        for ( ; i < l; i++ ) {
          name = attrNames[ i ];

          if ( name ) {
            propName = jQuery.propFix[ name ] || name;

            // See #9699 for explanation of this approach (setting first, then removal)
            jQuery.attr( this, name, "" );
            this.removeAttribute( jQuery.getSetAttribute ? name : propName );

            // Set corresponding property to false for boolean attributes
            if ( rboolean.test( name ) && propName in this ) {
              this[ propName ] = false;
            }
          }
        }
      }
    });
  };
})(jQuery);