var copyHTML:String = some_value_from_a_database_or_something_containing_html;
copyHTML = copyHTML.replace(/
/gm, "\n"); // fix double carriage returns 
copyHTML = copyHTML.replace(/’/g, "’"); // fix nasty apostrophes 
copyHTML = copyHTML.replace(/—/g, "—"); // fix evil en-dashes
copyHTML = copyHTML.replace(/–/g, "–"); // fix abominable em-dashes


var tf:TextField = new TextField();
tf.htmlText = copyHTML; // drink a beer

var copyHTML:String = some_value_from_a_database_or_something_containing_html;
copyHTML = copyHTML.replace(/
/gm, "\n"); // fix double carriage returns 
copyHTML = copyHTML.replace(/�/g, "’"); // fix nasty apostrophes 
copyHTML = copyHTML.replace(/�/g, "—"); // fix evil en-dashes
copyHTML = copyHTML.replace(/�/g, "–"); // fix abominable em-dashes


var tf:TextField = new TextField();
tf.htmlText = copyHTML; // drink a beer

var copyHTML:String = some_value_from_a_database_or_something_containing_html;
copyHTML = copyHTML.replace(/
/gm, "\n"); // fix double carriage returns 
copyHTML = copyHTML.replace(/’/g, "’"); // fix nasty apostrophes 
copyHTML = copyHTML.replace(/—/g, "—"); // fix evil en-dashes
copyHTML = copyHTML.replace(/–/g, "–"); // fix abominable em-dashes


var tf:TextField = new TextField();
tf.htmlText = copyHTML; // drink a beer

AS3 does some weird things with HTML.  Here are a few ways to handle common problems.  The worst offender that many people encounter is double carriage returns.  Regex those nasty buggers into oblivion (aka \n)!

AS3 HTML clean up

html

ActionScript 3