console 命令行工具 X clear

console

function moneyChange(e){

var number=$(e).val();
if (number.length>6){
    $(".btn").attr("disabled",false);
}


if(number.length>12){

$(".btn").attr("disabled",true);

}

};

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://lib.sinaapp.com/js/jquery/2.0.2/jquery-2.0.2.min.js"></script>
</head>
<body>
<input type="text" class="pay-text" placeholder="输入数字" oninput="moneyChange(this)">

<input type="button" class="btn" value="确认 "disabled="disabled">

</body>
</html>