代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<input type="text" id="btn" maxlength="25">
</body>
<script>
var btn = document.getElementById("btn");
btn.onblur=function(){
var val = btn.value;
if(/^[0-9]{11}$/.test(val)){
console.log("卡号不能为11位");
}else {
console.log("正确");
}
}
var tel = document.getElementById('btn');
tel.onkeyup = function () {
this.value = this.value.replace(/[^\d.]/g, ""); //只能输入数字或者小数点
this.value = this.value.replace(/\.{2,}/g, "."); //只能输入一个点 清除多余的
this.value = (this.value.match(/\d{0,7}(\.\d{0,2})?/) || [''])[0]; // 只能以数字开头（且最多只能输入7为整数）小数点后只能留2位;
if (this.value.indexOf(".") < 0 && this.value != "") { //如果没有小数点，首位不能为类似于 01、02的金额
this.value = parseFloat(this.value);
}
}
var u = navigator.userAgent, app = navigator.appVersion;
var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //android终端或者uc浏览器
var isiOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
if (isiOS) {
$("input[type='tel']").attr('type', 'number');
}
</script>
</html>
