Loading that giant blob of data is not a great plan, but if you must, here's the outline of how you might do it using jQuery's $.ajax() function.
<html><head>
<script src="jquery.js"></script>
<script>
getTxt = function (){
$.ajax({
url:'text.txt',
success: function (data){
//parse your data here
//you can split into lines using data.split('\n')
//an use regex functions to effectively parse it
}
});
}
</script>
</head><body>
<button type="button" id="btnGetTxt" onclick="getTxt()">Get Text</button>
</body></html>