However in this case, the link's ref attribute will be set to the value "null," and the link's text content will be hidden unless a flag to show null-link content is set to true.

但是，在这种情况下，这个链接的ref属性会设置为“null”值，而且链接的文本内容会隐藏起来，除非将显示空链接内容的标志设置为true。

youdao

The on-loan Chelsea winger was set to shoot but was felled by Carlisle, leaving ref Kevin Friend with little option but to award a penalty and show the defender a straight red.

BBC: Crystal Palace 5-0 Burnley