<style>

/*在chrome下移除input[number]的上下箭头*/

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button{
    -webkit-appearance: none !important;
    margin: 0;
}
/*在firefox下移除input[number]的上下箭头*/
input[type="number"]{-moz-appearance:textfield;}

<style>

<input type="number" oninput="if(value.length>5)value=http://www.mamicode.com/value.slice(0,5)">

input只能输入数字并限制长度