Common function collation in JavaScript

The judgment of 1.typeof, constructor and instanceof in the log group

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var arr = [1,5,6,9,8,5,4]; var arr = new Array (1,5,6,9,8,5,4); Console.log (typeof arr);//object Console.log (Arr.constructor ());//[] Console.log (arr instanceof Array);//true

2. Function from call

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(function (A, b) { Console.log (A + b);//30 from calling }) (10, 20); 3. Remove both sides of the space function Trim (str) { Return Str.replace (/^s+|s+$/g, ""); } Console.log (' Woshi sss ');//Woshi SSS Console.log (Trim (' Woshi sss '));//woshi SSS

4. Digital Judgment

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function Isnumber (n) { Return!isnan (parsefloat (n)) && isfinite (n); } Console.log (Isnumber (' e345 '));

5. Array judgment

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function IsArray (obj) { return Object.prototype.toString.call (obj) = = ' [Object Array] '; } Console.log (IsArray (arr));

6.length of understanding

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var myarray = [12, 222, 1000]; myarray.length = 0; MyArray will become an empty array [].-----length is a readable writable property

7, Base64_encode encryption, decryption

The code is as follows

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function Base64Encode (str) { var out,i,len,base64encodechars= "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789+/"; var c1,c2,c3; Len=str.length; i=0; Out= ""; while (I<len) { C1=str.charcodeat (i++) &0xff; if (I==len) { Out+=base64encodechars.charat (C1&GT;&GT;2); Out+=base64encodechars.charat ((c1&0x3) <<4); out+= "= ="; Break } C2=str.charcodeat (i++); if (I==len) { Out+=base64encodechars.charat (C1&GT;&GT;2); Out+=base64encodechars.charat ((c1&0x3) <<4) | ( (c2&0xf0) >>4)); Out+=base64encodechars.charat ((C2&AMP;0XF) <<2); out+= "="; Break } C3=str.charcodeat (i++); Out+=base64encodechars.charat (C1&GT;&GT;2); Out+=base64encodechars.charat ((c1&0x3) <<4) | ( (c2&0xf0) >>4)); Out+=base64encodechars.charat ((c2&0xf) <<2) | ( (C3&AMP;0XC0) >>6)); Out+=base64encodechars.charat (c3&0x3f); } return out; } function Base64decode (str) { var c1,c2,c3,c4,base64decodechars=new Array ( -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 , -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,- 1,-1,-1,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,- 1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1); var i,len,out; Len=str.length; i=0; Out= ""; while (I<len) { * C1 * * do{ C1=base64decodechars[str.charcodeat (i++) &0xff]; }while (I<len&&c1==-1); if (c1==-1) break; * C2 * * do{ C2=base64decodechars[str.charcodeat (i++) &0xff]; }while (I<len&&c2==-1); if (c2==-1) break; Out+=string.fromcharcode ((c1<<2) | ( (c2&0x30) >>4)); * C3 * * do{ C3=str.charcodeat (i++) &0xff; if (c3==61) return out; C3=BASE64DECODECHARS[C3]; }while (I<len&&c3==-1); if (c3==-1) break; Out+=string.fromcharcode ((c2&0xf) <<4) | ( (c3&0x3c) >>2)); * C4 * * do{ C4=str.charcodeat (i++) &0xff; if (c4==61) return out; C4=BASE64DECODECHARS[C4]; }while (I<len&&c4==-1); if (c4==-1) break; Out+=string.fromcharcode (((c3&0x03) <<6) |c4); } return out; } function Utf16to8 (str) { var out,i,len,c; Out= ""; Len=str.length; for (i=0;i<len;i++) { C=str.charcodeat (i); if ((c>=0x0001) && (c<=0x007f)) { Out+=str.charat (i); else if (c>0x07ff) { Out+=string.fromcharcode (0xe0| ( (c>>12) &0x0f)); Out+=string.fromcharcode (0x80| ( (c>>6) &0x3f)); Out+=string.fromcharcode (0x80| ( (c>>0) &0x3f)); } else { Out+=string.fromcharcode (0xc0| ( (c>>6) &0x1f)); Out+=string.fromcharcode (0x80| ( (c>>0) &0x3f)); } } return out; } function Utf8to16 (str) { var out,i,len,c; var char2,char3; Out= ""; Len=str.length; i=0; while (I<len) { C=str.charcodeat (i++); Switch (c>>4) { Case 0: Case 1: Case 2: Case 3: Case 4: Case 5: Case 6: Case 7: 0xxxxxxx Out+=str.charat (i-1); Break Case 12: Case 13: 110x xxxx 10xx xxxx Char2=str.charcodeat (i++); Out+=string.fromcharcode ((c&0x1f) <<6) | ( char2&0x3f)); Break Case 14: 1110 xxxx 10xx xxxx 10xx xxxx Char2=str.charcodeat (i++); Char3=str.charcodeat (i++); Out+=string.fromcharcode ((c&0x0f) <<12) | ( (char2&0x3f) <<6) | ((char3&0x3f) <<0)); Break } } return out; }

8. Date and Time

Getday function: Returns the day of the week, the value is 0~6, where 0 means Sunday, 1 means Monday, ..., 6 means Saturday. Cases:

The code is as follows	Copy Code
function Datedemo () { var d, Day, X, S = "Today is:"; var x = new Array ("Sunday", "Monday", "Tuesday"); var x = X.concat ("Wednesday", "Thursday", "Friday"); var x = x.concat ("Saturday"); D = new Date (); Day = D.getday (); Return (s + + x[day]); }

(3) Gethouse function: Returns the "Hour" section of the date, and the value is 0~23. Cases.

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function Timedemo () { var d, s = "The current Local:"; var c = ":"; D = new Date (); S + + d.gethours () + C; S + + d.getminutes () + C; S + + d.getseconds () + C; S + + d.getmilliseconds (); return (s); }

(4) getminutes function: Returns the "Minutes" section of the date, and the value is 0~59. See the above example.  
(5) getmonth function: Returns the "month" section of the date, and the value is 0~11. Of these, 0 said January, 2 means March, ..., 11 means December. See the previous example.  
(6) getseconds function: Returns the "Seconds" section of the date, and the value is 0~59. See the previous example.  
(7) gettime function: Returns the system time.