字符串
<!DOCTYPE html>
<html>
<head>
<title>js7.html</title>
</head>
<body>
<script type="text/javascript">
var str = "javascript";
var num = 1234;
with (document)
{
write(str.toUpperCase()+"<br>");
write(num.toString().charAt(2), "<br>");
write(str.substring(0,4), "<br>");
}
</script>
</body>
</html>
结果：
JAVASCRIPT
3
java
下面是验证email。如果包含@则认为正确。否则报错。
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
function isEmail()
{
var email = document.getElementsByName("email")[0].value;
if (email.indexOf("@") == -1)
{
alert ("请输入正确 email!");
}
else
{
alert ("Good!");
}
}
</script>
</head>
<body>
<form>
email: <input type = "text" name = "email">
<input type = "button" value = "check" onclick = "isEmail();">
</form>
</body>
</html>