Record keypress and response time without advancing

Question

I'm very new to JavaScript. I have a Qualtrics survey and I'm trying to create a question to which respondents must first press the spacebar, and then respond to a math problem on the screen. What I want is for Qualtrics to record (1) whether they press the spacebar (score as "C") or not (score as "X"), (2) if they do, how long it took them to press the spacebar from when the page appeared, and (3) to NOT advance to the next screen on the keypress, since they still have to answer the math problem on the screen. Here's what I've been trying:

Body of the Qualtrics question Q1:

Please press the spacebar, then solve this problem: 1+12+15-13-3+19-9=?

JavaScript associated with Qualtrics question Q1:

Qualtrics.SurveyEngine.addOnload(function()
{   
    var day = new Date();
    trialstart = day.getTime();

    $(document).on('keydown', function(e) {
        if(e.keyCode === 32) {
            var day = new Date();
            trialend = day.getTime();
            rt = trialend - trialstart;
            document.getElementById("Q1").value = document.getElementById("Q1").value + "C" + rt + ",";
        }
        else{
            document.getElementById("Q1").value = document.getElementById("Q1").value + "X" + ",";
        }
    });
});

Right now, this script isn't doing anything; Qualtrics outputs whatever is typed into the response textbox associated with Q1 (for responding to the math problem), but doesn't record whether they pressed the spacebar or their response time for pressing that key. Any help would be greatly appreciated. Thanks.

Answer 1

It is likely that you are seeing no output from this because you're using "Q1" as the ID. Qualtrics element ID's are actually a bit different from that, so the best way to find them is to preview your survey and inspect them using your browser to find the proper ID.

Now for a more full answer, your Javascript has no way to unbind the keypress event. So it will always end up as X, not C, unless they end their text entry with a space. Instead try something like this:

Qualtrics.SurveyEngine.addOnload(function(){
    var pageStart = new Date();
    var trialstart = pageStart.getTime();
    var that = this;
    that.hideNextButton();
    var para = document.createElement("footnote");
    var test = document.getElementById("Buttons");
    var node = document.createElement('input');
    var next = document.getElementById("NextButton");
    var rt;
    node.id = "newButton";
    node.type = "button";
    node.name = "newButton";
    node.value = "  Continue  ";
    var fired = 0;
    var spaceFirst = '';

    $(document).on('keydown', function(e) {
        if(fired != 1){
            if(e.keyCode === 32) {
                var day = new Date();
                var trialend = day.getTime();
                rt = trialend - trialstart;
                spaceFirst = 'C';
                fired = 1;
            }
            else{
                spaceFirst = 'X';
                fired = 1;
            }
        }else{}
    });

    node.onclick = function stuff(){
        if(spaceFirst == 'C'){
            document.getElementById("QR~QID1").value = document.getElementById("QR~QID1").value + ', ' + spaceFirst + ", " + rt;
        }else if(spaceFirst == 'X'){
            document.getElementById("QR~QID1").value = document.getElementById("QR~QID1").value + ', ' + spaceFirst;
        }else{}
        window.alert(document.getElementById("QR~QID1").value);
        that.clickNextButton();
    };
    para.appendChild(node);
    test.insertBefore(para, next);

});

What this does is, hides the next button from view and creates a new button in it's place. (You will need to style this button, id = "newButton", to match your current button). Then it listens for the first keydown event, if it is a space, then it sets a variable equal to C, otherwise it sets it equal to X. Then it disables the keydown listener so that it doesn't fire after every keypress.

When the new button is pressed, it adds the appropriate X or C and the page time. You can remove or comment out the alert, as it is just for testing/debugging purposes.