SOURCE

var app = new Vue({
    el: '#app',
    data() {
        return {
            inp_1: '',
            label_item: ['MC', 'MR', 'MS', 'M+', 'M-', '←', 'CE', 'C', '±', '√', 7, 8, 9, '/', '%', 4, 5, 6, '*', '∑', 1, 2, 3, '-', '', 0, '.', '+', '='],
            one: '',
            use: '',
            two: '',
            three: '',
        }
    },
    methods: {
        ceshi: function () {
            var thisobj = this;
            thisobj.inp_1 = '我点击了';

        },
        label_itP: function (label) {
            var thisobj = this;
            var number = parseInt(label);
            if (!isNaN(number)) {
                if (thisobj.use == '') {
                    thisobj.one += label;
                } else {
                    thisobj.two += label;
                }
            }
            else if (label == '+' || label == '-'||label == '/'||label == '*') {
                thisobj.use = label;
            }
            else if (label == '=') {
                if (thisobj.one == '' || thisobj.use == '' || thisobj.two == '') {
                    console.log('异常！');
                    return;
                }
                if (thisobj.use == '+') {
                    thisobj.inp_1 = (parseInt(thisobj.one) + parseInt(thisobj.two));
                    return;
                } else if (thisobj.use == '-') {
                    thisobj.inp_1 = (parseInt(thisobj.one) - parseInt(thisobj.two));
                    return;
                } else if (thisobj.use == '*') {
                    thisobj.inp_1 = (parseInt(thisobj.one) * parseInt(thisobj.two));
                    return;
                } else if (thisobj.use == '/') {
                    thisobj.inp_1 = (parseInt(thisobj.one) / parseInt(thisobj.two));
                    return;
                }
                thisobj.one = '';
                thisobj.two = '';
                thisobj.inp_1 = '';
                return;
            } else if (label == 'C' ||label == 'CE') {
                thisobj.one = '';
                thisobj.two = '';
                thisobj.three = '';
                thisobj.inp_1 = '';
                return;
            }
            else if (label == '←') {
                if (thisobj.two.length > 0) {
                    thisobj.two = thisobj.two.Substring(0, thisobj.two.Length - 1)
                } else if (thisobj.use.length > 0) {
                    thisobj.use = thisobj.use.Substring(0, thisobj.use.Length - 1)
                } else if (thisobj.one.length > 0) {
                    thisobj.one = thisobj.one.Substring(0, thisobj.one.Length - 1)
                } else if (thisobj.inp_1.length > 0) {
                    thisobj.inp_1 = thisobj.one.Substring(0, thisobj.inp_1.Length - 1)
                }
                return;
            }
            thisobj.inp_1 += label;
        }
    },
    mounted: function () {
        var thisobj = this;


    }
});

<div id="app" class="items">
	<div class="item-title">
		<div class="title-one">
			查看（V）
		</div>
		<div class="title-one">
			编辑（E）
		</div>
		<div class="title-one">
			帮助（H）
		</div>
	</div>
	<div class="item-group">
		<textarea type="text" class="inp" v-model="inp_1" disabled></textarea>
    </div>
    <div class="item-label">
        <label :class="label=='='?'dengyu':label=='0'?'ling':''" v-for="label in label_item" v-on:click="label_itP(label)">{{label}}</label>
    </div>
    <div class="item-btn">
        <input type="button" class="btn" value="点击" v-on:click="ceshi">
    </div>
</div>

.items{
    height: 400px;
    width: 350px;
    background: #f7f7f7;
    border: 1px #000 solid;
    border-radius: 5px;
}
.items .item-title{
    flex: 1;
    display: flex;
    padding: 5px 10px 1px;
    border-bottom: 1px #dddddd solid;
    
}
.items .title-one{
    height: auto;
    margin-right: 10px;
    padding-right: 10px;
    margin-bottom: 5px;
}
.items .item-group{
    height: 100px;
    width: 94%;
    text-align: center;
}
.items .item-group textarea{
    max-height: 100%;
    height: calc( 100% - 25px );
    width: calc( 100% - 25px );
    margin: 10px;
    border: 1px #3a3939 solid;
    text-align: left;
    resize: none;
    vertical-align: bottom
}
.items .item-btn{
    margin-left: 10px;
}
.items .item-btn .btn{
    background: #030705;
    width: 60px;
    text-align: center;
    color: #f4f4f4;
    border: none;
    border-radius: 5px;
    height: 25px;

}

.items .item-btn .btn:hover{
    background: #20c528;
    border: 1ps #20c528 solid;
}

.item-label{
    width: 90%;
    height: 300px;
    margin: 5px 10px;
}
.item-label label{
    width: 55px;
    height: 30px;
    text-align: center;
    float: left;
    border: 1px #918d8d solid;
    margin: 3px;
    background: #ddd;
    border-radius: 3px;
}
.item-label label:hover{
    background: #20c528;
    border: 1ps #20c528 solid;
    color: #eee
}
.item-label .dengyu{
    height: 6lm0px;
    max-height: 60px;
}
.item-label .ling{
    width: 118px;
    
}