Why is it throwing a meta tag on XMLHttpRequest?

Question

Computer networks

Hello, I'm doing XMLHttpRequest instead of issuing html template issuing meta tag with refresh

.twig file

setTimeout(function(){
        var 
        rq              = new XMLHttpRequest();
        rq.open('POST','/cms/include/widget.php?ajaxCall=1&locale=ru&widget=List&unique=x_widget_7',false);
        rq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
        rq.onload = function(){
            console.log(this.responseText);
        }
        rq.send('{% for name,value in widget.params %}params[{{ name }}]={{ value|url_encode }}&{% endfor %}')
    },1000);