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JavaScriptbuilt-in object
function
JavaScript (built-in object):
ArrayBooleanDateFunctionMath
NumberString
(function): eval()isFinite()
isNaN()parseInt()parseFloat()

JavaScriptNumber
P.C. Lin

Number
• Number
…
• Number
:
Number = ([value]);
Number = new Number ([value]);
: Number b 17
var b = new Number(17);

Number
Number :
• Number . Number ;
• Number . Number ( );
Number :
• Number.MAX_VALUE
• Number.MIN_VALUE
• Number.NAN
• Number.NEGATIVE_INFINITY
• Number.POSITIVE_INFINITY
• Number.prototype ,

Number
• toExponential(fractionDigits)
fractionDigits
• toFixed(fractionDigits)
fractionDigits
• toPrecision(precision) precision
• toString(radix)
radix
• toLocaleString()
• valueOf()

jsnumber.htm

jsnumber.htm
var a = 12345.6789;
a 12346.5789
a.toExponential(12)
12 ,
1.23456789000e+4e+4104
a.toFixed(3) ,
12345.679
a.toPrecision(7)
, 12345.68
var b = new Number(17); b Number , 17
b.toString(2) b2
, 1001
a.valueOf() a , 12345.6789
Number.MAX_VALUE Number ,
1.7976931348623157e+308
Number.MIN_VALUE Number 5e-324

jsnumber.htm

JavaScriptString
P.C. Lin

String
•
var s1 = “Hello!”;
“Hello!” s1
“Hello!” s1
• String
(1)String . String([]);
(2)String . new String([]);

String
String
:
• String . String
;
• String . String
( );
String
:
• String. fromCharCode([char0 [, char1[, …]]]);
char0 char1…
• String. prototype; ,
String
:
• length String
• prototype ,

String
1
• charAt(pos) pos
• charCodeAt(pos) pos 0
215
• concat([ 1 [, 2 [, …]]])
1, 2, …
• indexOf(searchString, position)
searchString -1 • lastIndexOf(searchString, position)
searchString
-1
• localeCompare(that) that
0

String
2
• match(regexp) regexp
null
• replace(sValue, rValue)
sValue ,
rValue
• search(regexp) regexp ,
(0 )
-1
• slice(start, end)
start (0
)end ( )
end
start
• split(separator, limit)
separator
limitlimit

String
3
• substring(start, end) start end
end
start
• toLocaleLowerCase()
• toLocaleUpperCase()
• toLowerCase()
• toString()
• toUpperCase()
• valueOf()

jsstring.htm

jsstring.htm
var s1 = "Hello!";
s1 "Hello!"
var s2 = new String("Good Morning!");
s2, "Good
Morning!"
s2.charAt(5) s2
5 , 0 , 'M'
s1.charCodeAt(1) s1 1 , 'e' ;
0x65, 101
s1.toLowerCase() s1
, "hello!"
s2.toUpperCase() s2
, "GOOD MORINIG!"
s2.substring(5) s2 5
s2
; "Morning!"
s2.substring(0,4) s2 1 ( 0) 4 (
3)
, "Good"
a = s2.split(" "); s2 " " a;
a[0]="Good", a[1]="Morning!"
s2.indexOf("nin") s2
"nin" , 8
s1.lastIndexOf("e") s1
, "e" , 1

jsstring.htm