JavaScript ?? ? ???? ???
?? ???
??? ?? ? ?? ??
== 2 == 3 SE
=== ?? ?? ( ?? ??? ?? ????? ???. ??) (2 === 2 TRUE) (2 === "2" FALSE )
!= ?? ??, <> 2 == 3 TRUE
> ; 3 FALSE
< 2 ?? < 3 TRUE
>= 2 ?? >= 3 FALSE
<= 2 ?? <= 3 TRUE
??? ???? ??? ? ????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
var a=5,b="5";
document.write(a==b);
document.write("<br />");
document.write(a===b);
document.write("<br />");
document.write(a!=b);
document.write("<br />");
document.write(a!==b);
</script>
</head>
<body>
</body>
</html>?? ???
??? ?? ? ?? ??
&& ?? AND (???) x = 2 y = 6 X &&; y & gt; 5 false
|| ?? ??(??) y = 6; x || y & gt; !(x > y) TRUE
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
<script type="text/javascript">
var a=5,b="5";
document.write(a&&b > 10);
document.write("<br />");
document.write(a||b <6);
document.write("<br />");
document.write(!(a>b));
</script>
</head>
<body>
</body>
</html>??? ???
JavaScript?? ?? ??? ?? ??? ?? ???? ??? ???? ???? ????.
Syntax
?? ??=(??)?value1:value2
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文網(wǎng)(php.cn)</title>
</head>
<body>
年齡:<input id="age" value="18" />
<p>是否達到上學年齡?</p>
<button onclick="myFunction()">點擊按鈕</button>
<p id="demo"></p>
<script>
function myFunction()
{
var age,voteable;
age=document.getElementById("age").value;
voteable=(age<7)?"年齡太小，繼續(xù)幼兒園":"年齡已達到，可以入學";
document.getElementById("demo").innerHTML=voteable;
}
</script>
</body>
</html>
