Which of the following is the structure of an if statement?

<script type="text/javascript">
x=4+"4";
document.write(x);
</script> 

What is the output.?

<script>
document.write(navigator.appCodeName);
</script>

What is the output?

<script language="javascript">
function x()
{
document.write(2+5+"8");
}
</script> 

What is the output?

<script type="text/javascript">
var s = "9123456 or 80000?";
var pattern = /\d{4}/;
var output = s.match(pattern);
document.write(output);
</script>

What is the output?