$(document).ready(function(){
 checkAvailable("https://d.xxx-xx-xxx.salesforceliveagent.com/chat/rest/Visitor/Availability?org_id=xxxxxxxxxxxxxxx&deployment_id=xxxxxxxxxxxxxxx&Availability.ids=[xxxxxxxxxxxxxx]");
 });

 function checkAvailable(URL)
 {
$.ajax({
    url: URL,
    type: "GET",
    beforeSend: function(xhr){
        xhr.setRequestHeader('X-LIVEAGENT-AFFINITY', "null");
        xhr.setRequestHeader('X-LIVEAGENT-API-VERSION', "41");
        },
    success: function(response) { alert('Success: ' + response); },
    error: function(req, err){ console.log('Error Message: ' + err); }
 });

 }