Specifying the LRECL= parameter should address input data line truncation condition, although you must consider the input data record content itself.
Share what code you have for your DATA step to parse the HTML.
As far as generating HTML, you can use a SAS DATA _NULL_ step to generate the HTML tags, or consider how you might use ODS HTML possibly, depending on your requirements. I have pasted a link to one of many technical papers found on the SAS support website
http://support.sas.com/ found using a search on related keywords with your post.
Scott Barry
SBBWorks, Inc.
http://www2.sas.com/proceedings/sugi27/p061-27.pdf