var a = 0.1 + 0.2, b = 0.5 - 0.2;
a === b // false

if(!Number.EPSILON) {
Number.EPSILON = Math.pow(2, -52);
}
function numberCloseEnoughToEqual(n1, n2) {
return Math.abs(n1 - n2) < Number.EPSILON;
}
var a = 0.1 + 0.2, b = 0.5 - 0.2;
numberCloseEnoughToEqual(a, b); //true

Function getLastDay(year,month) {var new_year = year;    //取当前的年份var new_month = month++;//取下一个月的第一天，方便计算（最后一天不固定）if (month > 12)            //如果当前大于12月，则年份转到下一年
        {new_month -= 12;        //月份减new_year++;            //年份增
        }var new_date = new Date(new_year, new_month, 1);                //取当年当月中的第一天var date_count = (new Date(new_date.getTime() - 1000 * 60 * 60 * 24)).getDate();//获取当月的天数var last_date = new Date(new_date.getTime() - 1000 * 60 * 60 * 24);//获得当月最后一天的日期return date_count;}

<div>用户名：<input id="username" type="text"/>密码： <input id="password" type="password"/><input id="submitBtn" type="button" value="提交"></button>
</div>

<script type="text/javascript">//后端开发中的AOP思想，同样可以应用在前端开发中
Function.prototype.before = function( beforefn ){// 保存原函数的引用var __self = this; return function(){// 执行新函数，新函数在原函数之前执行,且保证this 不被劫持，新函数接受的参数beforefn.apply( this, arguments ); // 执行原函数并返回原函数的执行结果，return __self.apply( this, arguments ); }
}//同理Function.prototype.after = function( afterfn ){var __self = this;return function(){var ret = __self.apply( this, arguments );afterfn.apply( this, arguments );return ret;}};</script>

<script>//应用场景var username = document.getElementById( 'username' ),password = document.getElementById( 'password' ),submitBtn = document.getElementById( 'submitBtn' );Function.prototype.before = function( beforefn ){var __self = this;return function(){if ( beforefn.apply( this, arguments ) === false ){// beforefn 返回false 的情况直接return，不再执行后面的原函数return;}return __self.apply( this, arguments );}}var validata = function(){if ( username.value === '' ){alert ( '用户名不能为空' );return false;}if ( password.value === '' ){alert ( '密码不能为空' );return false;}}var formSubmit = function(){var param = {username: username.value,password: password.value}ajax( 'http:// xxx.com/login', param );}formSubmit = formSubmit.before( validata );submitBtn.onclick = function(){formSubmit();}</script>

width:200px;
height:50px;
overflow : hidden;
text-overflow: ellipsis;
word-break: break-word
display: -webkit-box;
-webkit-line-clamp: 2;//自己设置的行数
-webkit-box-orient: vertical;

 <div class="dome">偷偷ce试 一下 enmmmmm</div>

//计算字符长度function  GetLeng(str){    var realLength = 0, len = str.length, charCode = -1;    for (var i = 0; i < len; i++) {        charCode = str.charCodeAt(i);        if (charCode >= 0 && charCode <= 128) realLength += 1;        else realLength += 2;    }    return realLength;}

//截取方法function CutStr(str,length,insert){    if(!str) return "";    if(length<= 0) return "";    if(!insert) insert = "";    var templen=0;    for(var i=0;i<str.length;i++){        if(str.charCodeAt(i)>255){            templen+=2;        }else{            templen++        }        if(templen == length){            return str.substring(0,i+1)+insert;        }else if(templen >length){            return str.substring(0,i)+insert;        }    }    return str;}//小使身手var domeText=$(".dome").text(),    domeTextLength = GetLeng(domeText);if(domeTextLength>18){    $(".dome").text(CutStr(domeText, 18, '...'))

}

<div class="#app">
<p>{{value.name}}</p>
</div>

{{value.name}}

<div class="#app" v-cloak>
<p>{{value.name}}</p>
</div>

[v-cloak] {
display: none;
}

[v-cloak] {
display: none !important;
}

<ul id="demo"><li v-for="item in list">{{item}}</div>
</ul>
new Vue({
el:'#demo',
data:{
list=[0,1,2,3,4,5,6,7,8,9,10]
},
methods:{
push:function(){
this.list.push(11);
this.nextTick(function(){
alert('数据已经更新')
});
this.$nextTick(function(){
alert('v-for渲染已经完成')
})
}
}})

this.$http.post(apiUrl)
.then((response) => {
if (response.data.success) {
this.topFocus.data = response.data.data;
this.$nextTick(function(){
//渲染完毕
});
}
}).catch(function(response) {
console.log(response);
});

var vm = new Vue({
el: '#example',
data: {
currentView: 'home'
},
components: {
home: { /* ... */ },
posts: { /* ... */ },
archive: { /* ... */ }
}
})
<component v-bind:is="currentView"><!-- 组件在 vm.currentview 变化时改变！ -->
</component>

<script>export default {data() {return {};},render: function(createElement) {let _type = bi.chart.data.type;let _attr = bi.chart.components[_type]["attr"];return createElement(_attr, {props: {}});}};
</script>