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?????? ???

JavaScript ???? ???? ???? ???? ? ?????.

JavaScript ???

???? "liu qi"? ?? ??? ??? ??? ? ????.

???? ??? ?? ??? ?? ??? ? ????. ????? ?? ????? ??? ? ????.

var carname = "????";
var carname = '?????';

?? ??? ???? ???? ? ??? ???? ? ????.

var ?? = carname[7];

???? ???? 0?? ?????. ?, ? ?? ?? ??? ?? [0], ? ?? ?? ??? ?? [1] ????.

???? ???? ??? ? ????. ???? ???? ???? ???? ??? ???.

var Answer = "It's alright";
var Answer = "He is been ' Johnny'";
var ?? = '?? "Johnny"?? ????';

???? ????? ??? ???? ???? ??? ?? ????.

Example

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>php中文網(wǎng)(php.cn)</title> 
</head>
<body>
<p id="demo"></p>
<script>
var x = 'It\'s alright';
var y = "He is called \"Johnny\"";
document.getElementById("demo").innerHTML = x + "<br>" + y; 
</script>
</body>
</html>

????? ???? ??? ???

??? ??

?? ?? ?? ??? ???? ??? ??? ??? ? ????.

Example

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>php中文網(wǎng)(php.cn)</title>
</head>
<body>
<script>
    var txt = "Hello World!";
    document.write("<p>" + txt.length + "</p>");
    var txt="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    document.write("<p>" + txt.length + "</p>");
</script>
</body>
</html>

????? ???? ??? ???

?? ??

JavaScript??? ???? ?????? ??? ????? ????.

? ??? ?? ?? JavaScript? ?? ??? ? ????.

?? ??? ???? ??? ?????? ??? ?? ????()? ???? "Vikings" ????? ????? ?????? ? ????.


"We are the ?? "Vikings" from the north."

????? ??? ???? ????????. . ????? ??? ?? ??? ??? ??? ?????.

????? ??()? ??????, ??, ??? ? ?? ?? ??? ??????? ? ??? ? ????.


?? ??? ????? ????? ??? ???? ?????? ? ?? ?? ??? ???? ????.

Enter ???? ??? ? ????????? JavaScript ???? ?? ??? ??? ???? ??? ? ????: var firstName = "John"??? ??? ??? var? ???? ???? ??? ??? ?? ????. firstName = new String("John" )
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>php中文網(wǎng)(php.cn)</title>
</head>
<body>
<p id="demo"></p>
<script>
    var x = "John";              // x是一個字符串
    var y = new String("John");  // y是一個對象
    document.getElementById("demo").innerHTML =typeof x + " " + typeof y;
</script>
</body>
</html>
????? ???? ??? ???: String ??? ??? ???. ?? ??? ???? ?? ???? ??? ? ????.
<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>php中文網(wǎng)(php.cn)</title> 
</head>
<body>
<p id="demo"></p>
<script>
var x = "John";              // x 是字符串
var y = new String("John");  // y 是一個對象
document.getElementById("demo").innerHTML = x===y;
</script>
<p>=== 為絕對相等，即數(shù)據(jù)類型與值都必須相等。</p>
</body>
</html>
????? ???? ??? ???. it=== ????? ?????. ?, ??? ??? ?? ?? ???? ???.
Codeoutput
'?????
"????
\????
n? ??
r
??
??? ?? ? ???

"John"? ?? ?? ? ????? ???? ????. ?? ? ???(??? ??? ???) ?? ?? JavaScript? ??? ? ????. JavaScript? ??? ? ??? ??? ? ?? ?? ??? ??? ? ?? ?????.

???? ??? ??? ??????. Chapters

Properties

Description

constructor

??? ??? ???? ??? ?????length

???? ??? ?????

prototype

? ???? ??? ? ????. ??? ??? ???


??? ???

???? ??
||
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>php中文網(wǎng)(php.cn)</title> </head> <body> <p id="demo"></p> <script> var x = 'It\'s alright'; var y = "He is called \"Johnny\""; document.getElementById("demo").innerHTML = x + "<br>" + y; </script> </body> </html>
MethodDescription
charAt()??? ??? ??? ?? ??? ?????
charCodeAt()??? ??? ??? ?? ??? ???? ?? ?????
cat()connection ? ? ??? ???, ??? ??? ??
fromCharCode()????? ???? ??
indexOf()????? ??? ??? ?? ???? ?? ?????.
lastIndexOf()????? ??? ??? ????? ???? ??? ?????.
localeCompare()? ???? ?? ?? ??? ??
match() ?? ?? ??? ??? ??
replacement()???? ???? ?? ??? ???
search()???? ???? ? ??
Slice() ??? ??? ???? ??? ??? ? ???? ??
Split()???? ?? ??? ??? ??
substr() ????? ??? ?? ?? ?? ?? ?? ????
substring()????? ??? ? ?? ?? ??? ??? ?????
toLocaleLowerCase()??? ??? ??? ?? ???? ???? ?????. ??? ??(?: ???)?? ??? ???? ??? ????.
toLocaleUpperCase() ???? ???? ?? ???? ???? ?????. ?? ??(?: ???)?? ??? ???? ??? ????.
toLowerCase() ???? ???? ??
toString() ??? ?? ?? ??
toUpperCase() ???? ???? ?? r Trim () ?? ? ?? ??? ??? ??
valueof () ??? ??? ?? ??? ??
<thead id="xjuqa"></thead>
    • <rp id="xjuqa"></rp>
        2. <var id="xjuqa"><strong id="xjuqa"></strong></var>
        <table id="xjuqa"><legend id="xjuqa"></legend></table>
      • <tfoot id="xjuqa"></tfoot>