test_communicate.js

function testFunc (form) {
    var x = form.n1.value;
    var y = form.n2.value;

    $.ajax({
        type: 'GET',            
        url: "http://127.0.0.1:5000/"+x+"-"+y,
        contentType: 'text/plain',
        success: function(response, textStat){
            response = "The total sum is" + response;
                $('.result').html(response);    
            }
    });
}