size1 = "Blank";

var hint = 'The difference in intensity (color) seen in these pixels is due to fluctuations in the background.';
var blank = 'You need to enter a value in the blank space.'

function checkme() {
    size1 = document.volume.answer.value;

    RightOnFile = './volume-correct.html';
    TryAgainFile = './volume-wrong.html';
    ReturnFile = './cygX1-image.html#return';

    if (!size1) {
    window.alert(blank);
    location = returnFile;
}

if ((size1 == "0") || (size1 == "0.0")) {
    location = RightOnFile;
}
else {
    location = TryAgainFile;
}
}