<script>, :
<!-- # 1: HTML -->
<html>
<head>
<title> HTML </title>
<script language="javascript">
<!--, JavaScript
//
// ; JavaScript -->
</script>
</head>
<body >
</body></html>
language . type, type "text/javascript":
<script type="text/javascript">
//JavaScript
</script>
script head, .. HTML- . script HTML. , , , .
, .js HTML- script
src, .
<script type="text/javascript" src="/jspr/pr.js"></script>
/jspr/ pr.js, .
JavaScript
alert() window,
OK , , confirm() prompt():
<!-- # 2: -->
<html> <head>
<title> </title>
<script type="text/javascript">
alert(" JavaScript alert()!");
confirm(" confirm, !");
prompt(" prompt(), ");
</script>
</head>
<body >
<P> <CENTER>
<H1 style="color:blue"> : alert(), confirm() prompt() </h1>
<HR><P><P>C </center>
</body> </html>
, .
MS Visual Studio, Internet Explorer Disable script debugging,
Advanced. debugger; Visual Studio, .
, Internet Explorer View > Script Debugger > Break at Next Statement, Visual Studio , - JavaScript.
( Microsoft) , , .
|
|
JavaScript var, :
var x;
:
x = Sample string;
JavaScript , :
y = Second string;
y , , .
JavaScript , , . , -
, .
JavaScript : Number ; String ; Boolean ; Undefined ; Null - . , .. . : , , .
JavaScript . 253 253, 1.7976 x 10308 2.2250 x 10-308.
.
, x, , 0 9 A F.
, Web .
JavaScript : 0, 0 7.
, Infinity . . , , .
NaN (not a number). , NaN, . , NaN, isNaN(), true, ( ), false, NaN.
, . :
Number.MAX_VALUE | |
Number.MIN_VALUE | |
Number.NaN | |
Number.POSITIVE_INFINITY | |
Number.NEGATIVE_INFINITY |
.
length, , :
|
|
charAt (index: Number): String , ;
concat ([ string1: String [, ... [, stringN: String]]]]): String ( +);
indexOf (subString: String [, startIndex: Number]): Number , , . , -1. , lastIndexOf(), ;
replace (rgExp: RegExp, replaceText: String): String ;
split ([ separator: { String | RegExp } [, limit: Number]]): Array . , , , , . ;
substr (start: Number [, length: Number]): String , ;
substring (start: Number, end: Number): String , , .
: true ; false . if. :
var doAlert = true;
if (doAlert) { alert(Hello, World!); }