<!DOCTYPE html>
<body>
<script>
str = "%#K%jz0i8t69v29h##K%vr7eoawzff0d##K%yu13m6zlqwwn##K%wuu9jkc54chc##K%kokiwgo9ybff#%";
LinkArr = str.replace(/^.*%#(?=K)|#%$/g,'').split(/##/ig);
//alert(LinkArr.join(',\n'));
function run() {
var tstart = new Date();
var L = LinkArr.length;
var str = '';
for(var i =0; i<500; i++) {
str+='<a href="'+LinkArr[0]+'">Текст</a><br />\n'
}//alert(str)
var p=document.createElement('p');
p.innerHTML=str;
document.body.appendChild(p);
alert(new Date() - tstart);
}
</script>
<button onclick="run()">Запуск</button>
</body>