This question already has an answer here:
I am getting this error in php which i quite don't understand why it is happening. Can anyone shed some light on why this is an error ? I am a beginner in php so please bear with me. Any sort of feedback would be greatly appreciated.
<!DOCTYPE html>
<head>
<title> Distance </title>
</head>
<body>
<?php
function distance($lat,$lng,$d){
$distannce = ($lat - $lng) / $d;
return $distannce;
}
$stand = distance(isset($_POST['val']),isset($_POST['value']),isset($_POST['dist']));
?>
<form method = "post">
<input type="checkbox" name="dtLatLng_Lat" checked="checked" />
<label for="dtLatLng_Lat"> Latitude </label>   
base
<input type="text"name="val" size ="6" style="width:60px"; />
dist
<input type="text"name="dis" id="dis" size = "1"; />
<label for="dis"> </label>
<br>
<input type="checkbox" name="dtLatLng" id="dtLatLng" checked="checked" />
<label for="dtLatLng"> Longitude </label> 
base
<input type="text" name="value" id="dtvalue" size ="6" style="width:60px";/>
<label for="dtvalue"> </label>
dist
<input type="text"name="dist" id="dtval" size ="1"; />
<br>
<input type="submit" name="submit" value="Submit" />
</form>
</body>
</html>
</div>
