why im cannt change this echo to innerHTML? the output unexpected '='

Question

if(pm_count=='50'){
$error='The user you are trying to send a message to has 50 private messages, sorry but we cant send your message untill that user deletes some of their messages.';
}else{
mysql_query("INSERT INTO messages(reciever,sender,subject,message) VALUES('$reciever', '$user','$subject', '$message')") or die(mysql_error());
$pm_count++;
mysql_query("UPDATE fb_users SET pm_count='$pm_count' WHERE username='$reciever'");
}
echo"<p><b>You have successfully sent a private message!</b></p><br>";
}
else{
$error = 'You must wait 15 seconds before sending another private message';
}

Answer 1

is it echo("")?
I know for javascript you need to retrieve the elemnt and change it to what you want. **assuming u want it to appear on the page..
js:

<b><p id="myId"></p></b><br>

document.getElementById("myId").innerHTML = "The message you wish to add";

will now be:

<b><p id="myId">The message you wish to add</p></b><br>

Answer 2

ive try, and the message "Call to undefined function getElementById"

Answer 3

there may be a php specific function that allows this to happen. :/ I've used php like once. sorry man.

Answer 4

please, explain it.