Why I have not the option to open the web Inspector interface - Safari? I want to open this interface to look the source code or response, like below:



But, when I want to open the localhost:8080/xxx's page, I found I do not able to open that, it is gray:



So, how to resolve it in Safari?
There's another way of showing the Web Inspector. 

Right/Secondary click on a web page and select: Inspect Element or Review the elements.