function createTabbable(fnRedirectFocus) {
			var oBlockSpan = document.createElement("span");

			oBlockSpan.setAttribute("tabindex", 0);
			oBlockSpan.classList.add("sapUiBlockLayerTabbable");
			oBlockSpan.addEventListener('focusin', fnRedirectFocus);

			return oBlockSpan;
		}
Create a tabbable span for the block section of the control with according focus handling.

@param {function} fnRedirectFocus Focus handling function
@returns {object} The span element's DOM node
@private