Do you really know JS?

1, SetTimeout

SetTimeout (function () {

}), 1000)

SetTimeout (function (num) {

Alert (num)//Bounce 123

},1000,123)

2. Stitching strings (using \)

Document.body.innerHTML = ' <div>div</div>\

<span>span</span>\

<p>p</p>\

55555 '

3. Console.log (in console output style%c)

var test = 123;

Console.log (test); Normal input Log text

Console.log ('%c ' +test, ' color:red;font-size:20px;background:blue ')//output text with style

4, typeof (to be called by the form of)

var test = 123;

typeof Test//number

typeof (Test)

Instanceof, in also have similar use method

5, nested for loop (jump out of the entire loop)

for (Var i=0;i<5;i++) {

for (Var j=0;j<1;j++) {

if (i==3) break;

Alert (i)

}

}

Result: 0,1,2,4, where 3 jumps out of the loop inside

Cc:for (var i=0;i<5;i++) {

for (Var j=0;j<1;j++) {

if (i==3) break cc;

Alert (i)

}

}

Results: 0,1,2

6, for (;;) parameter is not written is possible

for (Var i=0;i<5;i++) {

alert (i);

}

The rewrite of the no-write parameter is as follows:

var i=0;

for (;;) {

alert (i);

if (++i>=5) break;

}

7. Call

Call is used to change this point and, if not written, to indicate window Object

8, InsertBefore

if (!ali.length) {

First one

Oul.appendchild (OLi)

} else {

Oul.insertbefore (oli,ali[0])//If ali[0] is empty, then appendchild is one thing, so you can write directly: Oul.insertbefore (Oli,ali[0])

}

9, anonymous function self-execution (bitwise operators can also)

(function () {}) ()

~function () {} ()

!function () {} ()

+function () {} ()

10. Create objects (you can omit parentheses)

function Aaa () {}

var test = new Aaa ();

You can also var test = new Aaa;

System objects are also available:

var arr = new Array;

　　　　

　　

Do you really know JS?