'HTML jQuery Survey Form ends abruptly

I have written a html with jquery to create a survey form but everytime I come to the textarea it gives out a 404 Error. When I play around it seems something might be wrong with my ifs? Sorry for bad coding I am new.

What I've done so far. I have created the divs that contain the 6 questions. 3 of those questions are radio buttons and 2 are textareas and 1 are contact information. Everytime a question has been answered I created with jquery an animate that fades one div out and fades one div in. I had to write ifs to block the next button and thats all It worked very smoothly but as soon as I added some ifs all got kinda destroyed and deleting back the ifs keeps the error for some reason

the jsfiddle:

 [JSFiddle][1]

Any help is appreciated.

JSFiddle



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