Unexpected Identifier Error

I'm not sure why my code won't run. Here is my JavaScript code: ``` fuction update(id, value){ xmlhttp = new XMLHttpRequest(); xmlhttp.onreadystatechange=function(){ if(xmlhttp.readyState==4 && xmlhttp.status == 200){ document.getElementById("response").innerHTML=xmlhttp.responseText; }else{ document.getElementById("response").innerHTML= "AJAX Failed: " + xmlhttp.status; } } xmlhttp.open("GET","updatevis.php?id="+id+"&value="+value); document.getElementById("response").innerHTML="Sending Ajax Request"; xmlhttp.send(); } ``` This is my HTML form code: ``` <input type="checkbox" name="visible" id="'.$id.'" checked="'.$checked.'" onchange="update('.$id.', '.$visible.')" /> ``` The `id` would be anything from 1-whatever its auto increment, visible is a `int`, either 1 or 0 Checked is just my code to have it start checked or not I have already run this code through chrome and Firefox, chrome gave my two errors a Unexpected identifier on line 5 (the line where I define the function) and a `ReferenceError` saying the function is not defined, on line 30 (the checkbox one)