input标签最多只能输入两位小数

jq代码:

html代码:

<input type="text"  onkeyup="num(this)"  placeholder="请输入">

<script type="text/javascript">
    left_show(3, 6);

    function num(obj){
        obj.value = obj.value.replace(/[^\d.]/g,""); //清除"数字"和"."以外的字符
        obj.value = obj.value.replace(/^\./g,""); //验证第一个字符是数字
        obj.value = obj.value.replace(/\.{2,}/g,"."); //只保留第一个, 清除多余的
        obj.value = obj.value.replace(".","$#$").replace(/\./g,"").replace("$#$",".");
        obj.value = obj.value.replace(/^(\-)*(\d+)\.(\d\d\d\d\d\d\d\d).*$/,'$1$2.$3'); //控制可输入的小数
    }
</script>