I'd look
here for learning how to read a PHP file.
I'd look
here for learning how to split the lines into the data arrays you want.
Once you've read those pages you should be able to open the file, read it line by line, break each line into an array with the implode method and have the data accessible from the codebehind.
Create an array of arrays as you read stuff in. Once you get to that point I'll help you with the javascript/ajax stuff
Pseudo code:
while there is a line
{
read line, use implode to break the line into an array
put array into another array
}
return the array