Add a specific element before heading in Hatena blog article.

AddElementBeforeHeader.js

if (location.href.match(/michinoeki-mania\.com\/entry/)) { // Replace this with your blog domain
    var j=new Date();
    var f=j.getTime();
    var g="";
    switch (f%5) {
        case 0:
            g="Something 1";
            break;
        case 1:
            g="Something 2";
            break;
        case 2:
            g="Something 3";
            break;
        case 3:
            g="Something 4";
            break;
        case 4:
            g="Something 5";
            break;
    }
    var h="<div style='text-align:center;'>"+g+"</div>";
    var a=document.getElementsByTagName("h1");
    if (typeof(a[3]) != "undefined") {
        a[3].insertAdjacentHTML("beforebegin",h);
    }
}