trying to understand some codes related to window.onload in js
- by user2507818
<body>
<script language="javascript">
window.tdiff = []; fred = function(a,b){return a-b;};
window.onload = function(e){
console.log("window.onload", e, Date.now() ,window.tdiff,
(window.tdiff[1] = Date.now()) && window.tdiff.reduce(fred) );
}
</script>
</body>
Above code is taken from a site.
In firefox-console, it shows:
window.onload load 1372646227664 [undefined, 1372646227664] 1372646227664
Question:
For window.tdiff->[undefined, 1372646227664], why not:[], because when runs to code:window.tdiff, it is still an empty array?
For window.tdiff.reduce(fred)->1372646227664, window.tdiff = [undefined, 1372646227664], undefined - 1372646227664, should be NaN, why it shows 1372646227664?
