Tumblr blog widget help

I know a bit of HTML/CSS, but only the bare basics. I need help coding a 'widget' for my blog. It's a talksprite, like in a game. I want an interactive one on the bottom left corner of my blog, the kind that looks like it sticks to your toolbar and won't move even if you scroll. When clicked, it'll open a dialogue box and have the character talk, and have options for pre-made responses to interact. The character has a talking animation and can change expressions depending on what they say. Kind of like a dating simulator, but without the dating. I'm an artist so I can create the sprites and other art, I just don't know how to code it.

Theoretically, if it can be made, I'd just need the frameworks and a simple explanation on how to edit it if I need to make any modifications (adding dialogue, etc). Can anyone help me create something like this? Full credit for the coding will go to the creator.

Note: I made this account to request help in coding this, and I'm not entirely sure asking people to code things for me are allowed, since the FAQ/rules don't seem to address it. If it's not allowed, I apologize sincerely and will take my issue elsewhere.