code: function( iframe, options ) {
  		var sandbox = iframe.getAttribute("sandbox");
  		if (typeof sandbox === "string" && !sandboxAllow.test(sandbox)) {
  			if (options && options.force) {
  				iframe.removeAttribute("sandbox");
  			} else if (!options || options.force !== false) {
  				logError(sandboxMsg);
  				iframe.setAttribute("data-srcdoc-polyfill", sandboxMsg);
  			}
  		}
  	}
docs: Determine if the operation may be blocked by the `sandbox` attribute in
  some environments, and optionally issue a warning or remove the
  attribute.