Trump was explicit on #H1B last night in Detroit - here is the transcript with his remarks on the issue:
KELLY: Mr. Trump, your campaign website to this day argues that more visas for highly skilled workers would, quote, "decimate American workers". However, at the CNBC debate, you spoke enthusiastically in favor of these visas. So, which is it?
TRUMP: I'm changing. I'm changing. We need highly skilled people in this country, and if we can't do it, we'll get them in. But, and we do need in Silicon Valley, we absolutely have to have.
So, we do need highly skilled, and one of the biggest problems we have is people go to the best colleges. They'll go to Harvard, they'll go to Stanford, they'll go to Wharton, as soon as they're finished they'll get shoved out. They want to stay in this country. They want to stay here desperately, they're not able to stay here. For that purpose, we absolutely have to be able to keep the brain power in this country.
(APPLAUSE)
KELLY: So you abandoning the position on your website...
TRUMP: ... I'm changing it, and I'm softening the position because we have to have talented people in this country.
Source: https://www.washingtonpost.com/news/the-fix/wp/2016/03/03/the-fox-news-gop-debate-transcript-annotated/