window.onload = showform;

function showform()
{
  document.getElementById('ajaxbg').style.display = 'block';
  document.getElementById('ajaxdiv').style.display = 'block';

  document.getElementById('ajaxbg').style.width = '100%';
  document.getElementById('ajaxbg').style.height = document.body.clientHeight + 'px';

  document.getElementById('ajaxdiv').style.left = "50%";
  document.getElementById('ajaxdiv').style.top = "50%";

  document.getElementById('ajaxdiv').style.marginLeft = "-" + parseInt(document.getElementById('ajaxdiv').offsetWidth / 2) + "px";
  document.getElementById('ajaxdiv').style.marginTop = "-" + parseInt(document.getElementById('ajaxdiv').offsetHeight / 2) + "px";  
}

function hideform()
{
  document.getElementById('ajaxbg').style.display = 'none';
  document.getElementById('ajaxdiv').style.display = 'none';
  
  return false;
}

function ajaxcheck ()
{
  var regex = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
 
  if (document.getElementById('name').value == '')
  {
    alert('You must enter your name');
    return false;
  }
  else if (document.getElementById('email').value == '')
  {
    alert('You must enter your email address');
    return false;
  }
  else if (!regex.test(document.getElementById('email').value))
  {
    alert('You must enter a valid email address');
    return false;
  }
  else if (document.getElementById('phone').value == '')
  {
    alert('You must enter your phone number');
    return false;
  }
 
  return true;
}