Is it possible to use HTML as content of a feature attribute?

[BenjaminUdink_ten_Cate]

I created a popup like so: https://www.evernote.com/shard/s156/sh/eefb1ff2-76d2-4bed-9ff7-7af59e11182e/9f37a4b2f342bd6668dddf5f...
however, it seems that whenever I save it, it gets stripped bare as soon as I create an anchor tag. Is this maybe because the fieldtype used for the attribute, esriFieldTypeString?

I want to be able to request the html content of this attribute and post it to the rest API, but neither work. I've tried URL encoding the html but that got me nowhere. Is there a guide on how to properly escape the html string so the arcgis rest api will accept it? And which fieldtype should be used?