javascript基础(number.test)

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>jstest001</title>
	<script type="text/javascript">
	 document.write(1+'11');
	 ///////
	 var email=prompt("enter email:");
	 document.write(email.indexOf("@")+'<br/>'); //返回某个字符的位置,无则-1
	 ///////
	 var oldstring='helloworld';
	 var newstring=oldstring.substring(0,6);//1-7 截取
	 document.write(newstring);
     ///////
     var number=prompt("enter a number");
	 document.write("round"+Math.round(number));///四舍五入
	 document.write("ceil"+Math.ceil(number));///向上入
	 document.write("floor"+Math.floor(number));//忽视小数
	 ////////
	 document.write("<br/>");
	 var dicethrow=Math.round(Math.random()*5)+1;
	 document.write(dicethrow);
	 /////
	 document.write("you are running"+navigator.appName+navigator.appVersion);
	</script>
</head>
<body>
</body>
</html>

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