I'm having problems making a request to the open weather api. Here is a link weather app. I can't get any kind of error or response from the open weather api.

First, your browser is likely blocking your api request because codepen is loaded over https and your api request is over http. Second, the api link you are using returns a not found error. Try clicking this instead to see a working endpoint

http://api.openweathermap.org/data/2.5/weather?zip=94040,us&appid=50d54e81daa56776e1c12581b6b22d54

Finally, you should console log the response of the callback instead of the string "sucess"

$.getJSON(urlString, function(val){
    console.log(val);
})