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https://duo.com/https://duo.com/docs/duowebis it posible to html code in hfs yes, i'm not familura with duo nor its web api.
from what i see:
First Steps
Before starting:
Sign up for a Duo account.
Log in to the Duo Admin Panel and navigate to Applications.
Click Protect an Application and locate Web SDK in the applications list. Click Protect this Application to get your integration key, secret key, and API hostname. (See Getting Started for help.)
Download and install a supported client library (Python, Ruby, Classic ASP, ASP.NET, Java, PHP, Node.js, ColdFusion, Perl).
Use NTP to ensure that your server's time is correct.
you need to download and setup a client libary. (id recomend java)
and use the iframe souce form the document
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The problem, HFS at the moment doen't support php, not is ther a predeveloped webcode form there site for hfs to intergrate. you wil lahve to manualy code or contact them for html coding support to intergrate it into hfs.
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