Twitter Button count keeps resetting to 0

I wrote a script in javascript that injects the twitter button url into the DOM because the URL I share includes a dynamic parameter. That part works.

What doesn't work is the twitter count. It keeps resetting to 0.

Here is how I build the twitter button URL.

    var appendEl = document.getElementById(el),
        twitterScript = document.createElement('a'),
        share_url,
        defaults,
        text_length_allowed = 110,
        text_length;

    opts = opts || {};

    defaults = {
        text: ''
    };

    for (var key in defaults) {
        if (defaults.hasOwnProperty(key) && opts[key] === undefined) {
            opts[key] = defaults[key];
        }
    }

    text_length = opts['text'].length;

    if(text_length > text_length_allowed) {
        custom_text = opts['text'].substring(0, text_length_allowed) + '...'开发者_如何学C;
    } else {
        custom_text = opts['text'];
    }

    share_url = this.shareUrlHelper(shareUrl);
    share_url = share_url + 'random_tag=' + this.randomTag;

    twitterScript.setAttribute('href', 'http://twitter.com/share?text=' + escape(custom_text) + 
            '&url=' + encodeURIComponent(share_url) + '&counturl=' +  encodeURIComponent(shareUrl)) + 
            '&count=horizontal';
    twitterScript.setAttribute('class', 'twitter-share-button');
    twitterScript.innerHTML = 'tweet';

    appendEl.appendChild(twitterScript);

    var tweetButton = new twttr.TweetButton(twitterScript);
    tweetButton.render();

I passed in these parameters: text, url, counturl, count.

url is the URL with my dynamic parameter appended to it, and counturl is the URL with no parameters.

What am i doing wrong?

since it's a dynamic URL, it will keep resetting to 0 because twitter does the count based on the URL