document.addEventListener("DOMContentLoaded", function(event) {
    function httpGetAsync(theUrl, callback)
    {
        var time = new Date().getTime() / 1000;
        var nonce = randomString(32);
        var xmlHttp = new XMLHttpRequest();
        xmlHttp.open("GET", theUrl, true);
        var params = JSON.stringify(
            {oauth_consumer_key:'TKk4q4d0R_ChTSTgfJe__g'},
            {oauth_token:'nXF2cUc5nwnGh06V8W8ZmIAt2B5WPzUY'},
            {oauth_signature_method:'hmac-sha1'},
            {oauth_signature:'WkVTrSYhI0oChU-uyvvuldJPK0A'},
            {oauth_timestamp:time},
            {oauth_nonce:nonce}

        );

        xmlHttp.setRequestHeader("Content-type", "application/json; charset=utf-8");
        //xmlHttp.setRequestHeader("Content-length", params.length);
        xmlHttp.setRequestHeader('Access-Control-Allow-Origin','*');
        //xmlHttp.setRequestHeader("Connection", "close");
        xmlHttp.onreadystatechange = function() {
            if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
                alert(http.responseText);
        };
        xmlHttp.send(params);
    }

    var randomString = function(length) {
        var text = "";
        var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        for(var i = 0; i < length; i++) {
            text += possible.charAt(Math.floor(Math.random() * possible.length));
        }
        return text;
    };

    httpGetAsync('https://api.yelp.com/v2/search?term=food&location=San+Francisco');

    function something (text){
        console.log(text);
    }

});