SOURCE

var $input = $('input');
var $cal = $('#calculate');
var $res = $('#result .content');

var inputNum,copyTime=0,pasteTime=0;
$cal.on('click',function(){
    inputNum = $input.val();
    copyTime=0;
    pasteTime=0;
    cal(inputNum);
});

function cal(len){
    for(var i = 0; i < len; i++){
        
    }
}

<input type="text" />
<button id="calculate">计算</button>
<div id="result">
    结果:
    <div class="content"></div>
</div>

button{
    padding:5px 10px;
    border:solid 1px blue;
    background:none;
    border-radius:5px;
    color:blue;
    transition:all 0.38s;
    &:hover{
        color:#fff;
        background:blue;
    }
}