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JavaScript ?? ??

JavaScript Math ??

Math ??? JavaScript?? ???? ?? ??? ???? ? ?????.

String ? Date ??? ?? Math ??? ??? ???? ??? ??? Math()? ???? Math ??? ?? ??? ??? Math ??? ?? ??? ? ????. ????? Math ??? ???? ?? ?????? Math.function? ?? ?? ??? ? ????.

Math ?? ??

JavaScript? ????? ???? ?? ?? ?? ???? Math ??? 8?? ??? ?????.


?? e, ?? ?? Math? ?????. LN2 2? ?? ??(?? 0.693? ??)

Math.LN10 10? ?? ??(?? 2.302? ??)

Math.LOG2E ?? 2? e? ? ??(?? 1.414? ??)

Math .LOG10E ?? 10? ???? ? e? ??(?? 0.434? ??)

Math.PI Pi(?? 3.14159? ??)

Math.SQRT1_2 2? ???? ??(?? 0.707? ??)

Math .SQRT2 2? ???(?? 1.414? ??)

Math? ?? ??

Math ??? ? ??? ?? ??? ? ????. 

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>php中文網(wǎng)(php.cn)</title> 
<script type="text/javascript">
      var pi = Math.PI;
    document.write(pi);
</script>
</head>
<body>
</body>
</html>

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

3.14159265 3589793

?? ???


Math ???? ??? ? ?? ?? ? ??? ??? ? ?? ?? ??(???)? ????.

?? ???? Math ??? round ???? ???? ??? ??????.
document.write(Math.round(4.7));

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

5

?? ???? Math ??? random() ???? ???? ?? ?????. 0? 1 ??? ??? ?? ??:

document.write(Math.random());

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

0.897235837765038

?? ????? Math ??? Floor() ???? random()? ???? 0? 11 ??? ??? ?????.

document.write(Math.floor(Math.random ()* 11));

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

2

???? ??
||
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>php中文網(wǎng)(php.cn)</title> <script type="text/javascript"> document.write( Math.round(Math.E) + "<br />" ); document.write(Math.round(0.3) + "<br />") document.write( Math.round(0.9) + "<br />" ); document.write( Math.round(-10.5) + "<br />" ); document.write( Math.round(10.5) ); </script> </head> <body> </body> </html>