proposal for xui3

xui-3.0.0.js

var ie = (function(){
    var undef
    ,   v = 3
    ,   div = document.createElement('div')
    ,   all = div.getElementsByTagName('i')

    while (
        div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
        all[0]
    )
    return v > 4 ? v : undef;
}())

if (ie) {
    document.write('<script src=//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js><\/script>')
}
else {
    document.write('<script src=js/zepto.min.js><\/script>');
}