function showPDF(numPassed) {
    if (numPassed == 1) {
        document.getElementById('pdf1').style.display = "block";
    }
    else if (numPassed == 2) {
        document.getElementById('pdf2').style.display = "block";
    }

    else if (numPassed == 3) {
        document.getElementById('pdf3').style.display = "block";
    }
  
  else if (numPassed == 4) {
        document.getElementById('pdf4').style.display = "block";
    }
}

function hidePDF(numPassed) {
    if (numPassed == 1) {
        document.getElementById('pdf1').style.display = "none";
    }
    else if (numPassed == 2) {
        document.getElementById('pdf2').style.display = "none";
    }
    else if (numPassed == 3) {
        document.getElementById('pdf3').style.display = "none";
    }
  else if (numPassed == 4) {
        document.getElementById('pdf4').style.display = "none";
    }
}