<!DOCTYPE html>
<html >
<head>
<meta charset="UTF-8">
<title>判断是否是数字</title>
</head>
<body>
<input type="text" class="inputText">
<script>
var inputText = document.querySelector(".inputText");
inputText.addEventListener('input', function(){
if(isNum(inputText.value))
{
console.log("It is a number.");
}
else
{
console.log("It's not a number.");
}
});
function isNum(num)
{
var retNum = /^\d*$/;
return retNum.test(num);
}
</script>
</body>
</html>
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