1.日期类
按照2017-03-01的格式
function formdate(dt){
if(!dt){
dt=new Date();
}
var year=dt.getFullYear();
var month=dt.getMonth()+1;
var date=dt.getDate();
if(month<10){month='0'+month;}
if(date<10){date='0'+date;}
return year+'-'+month+'-'+date;}
console.log(formdate(new Date()));
计算当年还剩多少时间
function counter() {
var date = newDate();
var year = date.getFullYear();
var date2 = newDate(year, 11,31,23,59,59);
/*转换成秒*/
var time = (date2 - date) / 1000;
var day = Math.floor(time / (24* 60* 60))
var hour = Math.floor(time % (24* 60* 60) / (60* 60))
var minute = Math.floor(time % (24* 60* 60) % (60* 60) / 60);
var second = Math.floor(time % (24* 60* 60) % (60* 60) % 60);
var str = year + "年还剩"+ day + "天"+ hour + "时"+ minute + "分"+ second + "秒";
console.log(str);
}
## 2.Math
获取随机数，要求长度一直是固定的(Math.random())
var random=Math.random();
random=random+“0000000000”;
random=random.slice(0,10);
console.log(random);
## 3.数组API
写一个能便利对象和数组的forEach函数
function forEach(obj,fn){
if(obj instanceof Array){
obj.forEach(function(item,index){
fn(index,item)}
)}else{
for(key in obj){if(obj.hasOwnProperty(key)){fn(key,obj[key]);}
console.log();}
}}
var arr=[1,2,3];
forEach(arr,function(index,item){
console.log(index,item);})
var obj={x:100,y:200}
forEach(obj,function(key,val){
console.log(key,val);})
我是一个DIV
function fun(obj){ var div = document.getElementById("test"); if(obj.value=="隐藏"){ div.style.display = "none"; obj.value = "显示"; } else { div.style.display = "block"; obj.value = "隐藏"; } } ```
<body>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
<script>
var l=document.querySelectorAll("li");
for(var i=1;i<l.length;i++){
(function(i){
l[i].addEventListener("click",function(){
alert(i);
},false);
})(i);
}
</script>
</body>
事件类
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>tuozhuai</title>
<style>
*{
margin: 0px;padding: 0px;
}
#div1{
width: 100px;
height: 100px;
background: red;
position: absolute;
}
</style>
</head>
<body>
<div id="div1"></div>
<script>
function drag(id) {
var odiv=document.getElementById(id)
odiv.onmousedown=function (ev) {
var ev=ev||event;
var disX=ev.clientX-odiv.offsetLeft;
var disY=ev.clientY-odiv.offsetTop;
document.onmousemove=function (ev2) {
var ev2=ev2||event;
var left=ev2.clientX-disX;
var top=ev2.clientY-disY;
var w = document.documentElement.clientWidth || document.body.clientWidth;
var h = document.documentElement.clientHeight || document.body.clientHeight;
if(left > w - odiv.offsetWidth){
left = w - odiv.offsetWidth
}
if(left< 0){
left = 0;
}
if(top< 0){
top = 0;
}
if(top > h - odiv.offsetHeight){
top = h - odiv.offsetHeight
}
odiv.style.left=left+"px";
odiv.style.top=top+"px"
}
document.onmouseup=function (ev2) {
document.onmousemove=null
}
}
}
drag("div1")
</script>
</body>
</html>