resizeEvt = "orientationchange" in window ? "orientationchange" : "resize",I checked the JS manual. There is no orientationchange property in the window object. Why can it be detected when the screen is rotated?
here is the source code:
(function(doc, win) {
var docEl = doc.documentElement,
resizeEvt = "orientationchange" in window ? "orientationchange" : "resize",
recalc = function() {
var clientWidth = docEl.clientWidth;
if (!clientWidth) return;
if (clientWidth >= 640) {
docEl.style.fontSize = "100px";
} else {
docEl.style.fontSize = 100 * (clientWidth / 640) + "px";
}
};
if (!doc.addEventListener) return;
win.addEventListener(resizeEvt, recalc, false);
doc.addEventListener("DOMContentLoaded", recalc, false);
recalc();
})(document, window);