?????? ??
JavaScript ?? ?
JavaScript??? ?? ??, ?? ??, ???? ??? ? ?? ??? ??? ??? ?? ? ????.
?? ??
?? ??? ???? ?? ??? ?? ? ??? ???? ? ?? ?????.
?? ??? ???? ???? ?? ??? ???? ??? ??? ? ????.
Syntax
window.alert("sometext");
window.alert() ???? window ?? ? Alert() ??? ?? ?? ??? ? ????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script>
function myFunction(){
alert("警告框！");
}
</script>
</head>
<body>
<input type="button" onclick="myFunction()" value="顯示警告框" />
</body>
</html>?? ??
?? ??? ????? ??? ??? ?????? ???? ? ?????.
?? ??? ???? ???? "??" ?? "??"? ???? ??? ??? ??? ? ????.
"??"? ???? ?? ??? true? ?????. "??"? ???? ?? ??? false? ?????.
Syntax
window.confirm("sometext");
window.confirm() ???? window ?? ?? ?? ??() ???? ??? ? ????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>點擊按鈕，顯示確認框。</p>
<button onclick="myFunction()">點我</button>
<p id="demo"></p>
<script>
function myFunction(){
var x;
var r=confirm("按下按鈕!");
if (r==true){
x="你按下了\"確定\"按鈕!";
}
else{
x="你按下了\"取消\"按鈕!";
}
document.getElementById("demo").innerHTML=x;
}
</script>
</body>
</html>???? ??
???? ??? ???? ???? ?? ????? ?? ?? ????? ???? ???? ? ?? ?????.
???? ??? ???? ???? ?? ?? ??? ?? ?? ?? ?? ??? ???? ??? ??? ? ????.
???? ??? ???? ??? ?? ?????. ???? ??? ???? ?? ?? null???.
Syntax
window.prompt("sometext","defaultvalue");
window.prompt() ???? window ?? ? Prompt() ??? ?? ?? ??? ? ????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>點擊按鈕查看輸入的對話框。</p>
<button onclick="myFunction()">點我</button>
<p id="demo"></p>
<script>
function myFunction(){
var x;
var person=prompt("請輸入你的名字","Harry Potter");
if (person!=null && person!=""){
x="你好 " + person + "! 今天感覺如何?";
document.getElementById("demo").innerHTML=x;
}
}
</script>
</body>
</html>Line break
?? ???? ???? + "n"(n)? ???? ? ??? ?????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>點擊按鈕在彈窗總使用換行。</p>
<button onclick="myFunction()">點我</button>
<p id="demo"></p>
<script>
function myFunction(){
alert("Hello\nHow are you?");
}
</script>
</body>
</html>
