var numberOfPagesInput = document.getElementById("number-of-pages");
var increaseImg = document.getElementById("increase");
var decreaseImg = document.getElementById("decrease");
var resultSpan = document.getElementById("pricing-results");

numberOfPagesInput.value = 1;

function increasePages()
{
if (numberOfPagesInput.value < 30)
{
numberOfPagesInput.value++;
if (numberOfPagesInput.value == 1)
{
resultSpan.innerHTML = "<del>$150</del> $75";
}
else if (numberOfPagesInput.value == 2)
{
resultSpan.innerHTML = "<del>$300</del> $150";
}
else {
resultSpan.innerHTML = "<del>$" + (300 + (75 * (numberOfPagesInput.value - 2))) + "</del>" + "$" + (150 + (45 * (numberOfPagesInput.value - 2)));
}
}
return false;
}

function decreasePages()
{
if (numberOfPagesInput.value > 1)
{
numberOfPagesInput.value--;
if (numberOfPagesInput.value == 1)
{
resultSpan.innerHTML = "<del>$150</del> $75";
}
else if (numberOfPagesInput.value == 2)
{
resultSpan.innerHTML = "<del>$300</del> $150";
}
else {
resultSpan.innerHTML = "<del>$" + (300 + (75 * (numberOfPagesInput.value - 2))) + "</del>" + "$" + (150 + (45 * (numberOfPagesInput.value - 2)));
}
}
return false;
}

increaseImg.onclick = increasePages;
decreaseImg.onclick = decreasePages;