void increment(int x) {
    ++x;
}

main {
int x = 5;
increment(x);
printf("X is now: %d\n", x);
}

x=1
++x; // X is now two
x++; // X is now three, after this statement executes

x=1;
printf("x: %d\n", x);
printf("x: %d\n", ++x);
printf("x: %d\b", x++);
printf("x: %d\n", x);

for (int i=0; i < 100; i++)
{
 for (int j=0; j < 50; j++)
{
...
}
}

loop1:
loop2:
    .... do stuff
j = j+1
if j == jmax: (j=0, i+=1, goto loop1) else goto loop2

$.ajax(
    url: "upload.php",
    type: "POST",
    data: { 'u': <?php echo $userid; ?>, 'v': value}
);

<script type="text/javascript">
    var userid = '<?php echo $userid; ?>';
</script>

//note that the userid variable must be set elsewhere on the page
$.ajax(
    url: "upload.php",
    method: "POST",
    data: { 'u': userid, 'v': value}
);

var xhttp = new XMLHttpRequest();
            xhttp.open("POST", "upload.php", true);
            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            xhttp.send("v=" + value);