Why dataType: "text" doesn't bypass cors like "jsonp"

Why dataType: "text" doesn't bypass cors like "jsonp"

With the script below to get text string from a small hardware device over wifi.
The device is configured as a wifi AP & does not respond to browser request, it just updates its web data every second. I can see the data string with ip address in web page(refresh = new data)  &  a script tag will receive as valid data. <script type="text/javascript" src="">  </script>
The text string is structured as multi line JS variables & is valid json.

Problem is I need to use type: "jsonp" so I don't get cors blocked but it then parses the response that for some reason is not conforming to json (even tho the data from device is valid json
I have yet to find a way to view what is actually being parsed as the Console Response Payload shows empty.
I don't care too much if the response is modified when it is assigned to my final variable as I can "parse" it / error check in JS.

  1. <script>
        var RetStr // enable access to data outside ajax
        url: "",
        dataType: "jsonp", // <-- dataType: "text",   gives cors error (tried "jsonp text", also)

        // process response
        success: function( response ) {
            retVal1 = "Response data = " + response
            document.getElementById('varString').innerHTML =  retVal1;
        //    RetStr = responsetext  //???

         error: function( response,err ) {
            errVal1 = "Error data = " + response.status
            errVal2 = "Error type = " + err
            console.log(errVal1 + " , " + errVal2);
            document.getElementById('varString').innerHTML = errVal1 + " , " + errVal2;


The above is working to the point where I get error 200 & parsererror.
I have seen some example of side stepping the json parse but I can't apply it to my example above. Long time VB programmer, just a few weeks JS.

The script from “” was loaded even though its MIME type (“”) is not a valid JavaScript MIME type.
Error data = 200 , Error type = parsererror