5887 ? S(n, u)
5888 : t === Z
5889 ? A(n, s)
5890 : t === $ && S(n, s)); 5891 }
5892 function M(t, e) {
5893 try {
5885 ? w(n, s)
5886 : c === !1
5887 ? S(n, u)
5888 : t === Z 5889 ? A(n, s)
5890 : t === $ && S(n, s));
5891 }
6000 ? S(n, u)
6001 : t === Z
6002 ? A(n, s)
6003 : t === $ && S(n, s)); 6004 }
6005 function M(t, e) {
6006 try {
5998 ? w(n, s)
5999 : c === !1
6000 ? S(n, u)
6001 : t === Z 6002 ? A(n, s)
6003 : t === $ && S(n, s));
6004 }
11851 g[0].focus();
11852 })),
11853 (l.escKey = t(document, "keyup", function () {
11854 var e = e || window.event,11855 n = (function (e, n) {
11856 return (
11857 "undefined" != typeof getComputedStyle
It is recommended to use a variable only after it is defined as it might produce errors at runtime.
In JavaScript, prior to ES6, variable and function declarations are hoisted to the top of a scope, so it's possible to use identifiers before their formal declarations in code. This can be confusing and some believe it is best to always declare variables and functions before using them.
In ES6, block-level bindings (let
and const
) introduce a "temporal dead zone" where a ReferenceError
will be thrown with any attempt to access the variable before its declaration.
alert(a);
var a = 10;
f();
function f() {}
function g() {
return b;
}
var b = 1;
{
alert(c);
let c = 1;
}
var a;
a = 10;
alert(a);
function f() {}
f(1);
var b = 1;
function g() {
return b;
}
{
let c;
c++;
}