function validateSFForm(theForm) {
  // add the name of each field you want to require
  // for custom fields, use the Salesforce field ID
  var required = ["first_name", "last_name", "email"];
  var invalid = false;
  for (var i in required) {
    var theField = theForm[required[i]];
    if (theField.value == "") {
      theField.parentNode.className = "invalid";
      if (!invalid) theField.focus();
      invalid = true;
    } else {
      theField.parentNode.className = "";
    }
  }
  if (invalid) {
    alert("Indtast venligst en værdi i de markerede felter");
    return (false);
  } else {
    return (true);
  }
}

function getQueryVariable(variable) 
{ 
var query = window.location.search.substring(1); 
var vars = query.split("&"); 
for (var i=0;i<vars.length;i++) 
{ 
var pair = vars[i].split("="); 
if (pair[0] == variable) 
{ 
return pair[1]; 
} 
} 
}