Thank you so much for your review, and I'm super grad to be of your help!
Your opinion is very wonderful, I want to do so too.
I'm researching good way to realize it, so please wait for a while :)

2018.11.28:
Hi, 4e7ddd.
I'v tried to impliment your request, but I noticed one serious problem occur.
If you open new web-page , the new page has very large amount of text, this extention can not finish highlight process within practical time, then alert message is shown by browser.
so I implemented the second best, it is add one more shortcut to toggle highlight on-off to prevent user open extentions popup and click 'search' button at every time user refresh and open page.
Thank you.