$(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); }
     });

}