var last_ticker_val = null;
setInterval(function(){
    if(document.querySelector(bid_ask_label_selector) !== null){
        //console.log(document.querySelector(bid_ask_label_selector).innerHTML);
        var ticker_val = document.querySelector(bid_ask_label_selector).innerHTML;
        var up = 'up';
        var down = 'down';
        
       // console.log(last_ticker_val - ticker_val);
        
        if(minus_diff >= (ticker_val - last_ticker_val)){
            chrome.storage.local.set({deal: down}, function() {
                //console.log('Value is set to ');
            });
        }
        
        if((ticker_val - last_ticker_val) >= diff){
            chrome.storage.local.set({deal: up}, function() {
                //console.log('Value is set to ');
            });
        }
        
        last_ticker_val = ticker_val;
        
        
    }
},interval);

var last_ticker_val = null;

var last_ticker_val = 1; // Т.е. любое число