19.请输入整数

<!DOCTYPE html>
<html  >
<head lang="en">
    <meta charset="UTF-8">
    <title>T61-请输入整数</title>

</head>
<body>
<input type="text" id="num" onblur="myBlur()" onfocus="myFocus()"/>
<p id="p"></p>


</body>


<script type="text/javascript">


    var myBlur=function(){
//        var reg=/^-?d+$/;//整数
         var reg=/^d+$/;//正整数
       var str=document.getElementById("num").value;
//        console.log("检验正则"+reg.test(str));

        if(isNaN(str)){

            document.getElementById("p").innerHTML="请输入数字";
            document.getElementById("num").value="";


        }else if(!reg.test(str)){
            document.getElementById("p").innerHTML="请输入整数";
            document.getElementById("num").value="";

        }else{
            document.getElementById("p").innerHTML="输入正确";
        }
    }
    var myFocus= function () {
        document.getElementById("p").innerHTML="";
    }

</script>

</html>