I've been getting undefined error and I dont know how to fix it.
Here's my code:
<script type="text/javascript">
function returnBlurayDisc(member_id){
var xmlhttp;
if (window.XMLHttpRequest){
xmlhttp=new XMLHttpRequest();
}else{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4 && xmlhttp.status==200){
document.getElementById("popup_container").innerHTML=xmlhttp.responseText;
$("#GrayBackground").css({'height':'1900px','display':'inline'});
}
}
xmlhttp.open("GET","ajax/returnAjax.php?member_id="+member_id+"&name="+name);
xmlhttp.send();
}
</script>
The error is Uncaught ReferenceError: $ is not defined. Kindly help me.