js截取字符串计算

程序员文章站 2022-06-01 15:14:23

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<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			window.onload = function(){
				var pt = document.getElementById('pt');
				var btn = document.getElementById('btn');
				btn.onclick = function(){
					var value = pt.value;
					// console.log(value);
					// pt.substr(0,1);
					console.log(value.substr(0,1));
					console.log(value.substr(1,1));
					console.log(value.substr(2,1));
					alert(Number(value.substr(0,1)) + Number(value.substr(1,1)) + Number(value.substr(2,1)));
				}
				
			}
		</script>
	</head>
	<body>
		请输入一个3位数：
		<input type="text" name="" id="pt" value="" />
		<button type="button" id="btn">计算</button>
	</body>
</html>

js截取字符串计算