Analysis of javascript Functions used in discuz [original] Page 1/2 _ javascript skills

The js used in discuz is very good in compatibility and practicability of multiple browsers. We recommend you read var lang = new Array ();
Var userAgent = navigator. userAgent. toLowerCase ();
Var is_opera = userAgent. indexOf ('Opera ')! =-1 & opera. version ();
Var is_moz = (navigator. product = 'gecko ') & userAgent. substr (userAgent. indexOf ('Firefox') + 8, 3 );
Var is_ie = (userAgent. indexOf ('msie ')! =-1 &&! Is_opera) & userAgent. substr (userAgent. indexOf ('msie ') + 5, 3 );

Function $ (id ){
Return document. getElementById (id );
}
// Define the push attribute of the array
Array. prototype. push = function (value ){
This [this. length] = value;
Return this. length;
}
// Select all functions in javascript
Function checkall (form, prefix, checkall ){
Var checkall = checkall? Checkall: 'chall ';
For (var I = 0; I <form. elements. length; I ++ ){
Var e = form. elements [I];
If (e. name & e. name! = Checkall &&(! Prefix | (prefix & e. name. match (prefix )))){
E. checked = form. elements [checkall]. checked;
}
}
}

Function doane (event ){
E = event? Event: window. event;
If (is_ie ){
E. returnValue = false;
E. cancelBubble = true;
} Else if (e ){
E. stopPropagation ();
E. preventDefault ();
}
}

Function fetchCheckbox (cbn ){
Return $ (cbn) & $ (cbn). checked = true? 1: 0;
}

Function getcookie (name ){
Var cookie_start = document. cookie. indexOf (name );
Var cookie_end = document. cookie. indexOf (";", cookie_start );
Return cookie_start =-1? '': Unescape (document. cookie. substring (cookie_start + name. length + 1, (cookie_end> cookie_start? Cookie_end: document. cookie. length )));
}

Function thumbImg (obj ){
Var zw = obj. width;
Var zh = obj. height;
If (is_ie & zw = 0 & zh = 0 ){
Var matches;
Re =/width = (["']?) (\ D +) (\ 1)/I;
Matches = re.exe c (obj. outerHTML );
Zw = matches [2];
Re =/height = (["']?) (\ D +) (\ 1)/I;
Matches = re.exe c (obj. outerHTML );
Zh = matches [2];
}
Obj. resized = true;
Obj. style. width = zw + 'px ';
Obj. style. height = 'auto ';
If (obj. offsetHeight> zh ){
Obj. style. height = zh + 'px ';
Obj. style. width = 'auto ';
}
If (is_ie ){
Var imgid = 'img _ '+ Math. random ();
Obj. id = imgid;
SetTimeout ('try {if ($ (\ ''+ imgid + '\'). offsetHeight> '+ zh +') {$ (\ ''+ imgid + '\'). style. height = \ ''+ zh + 'px \ '; $ (\'' + imgid + '\'). style. width = \ 'Auto \ '; }}catch (e) {}', 1000 );
}
Obj. onload = null;
}

Function imgzoom (obj ){}

Function in_array (needle, haystack ){
If (typeof needle = 'string' | typeof needle = 'number '){
For (var I in haystack ){
If (haystack [I] = needle ){
Return true;
}
}
}
Return false;
}

Function setcopy (text, alertmsg ){
If (is_ie ){
ClipboardData. setData ('text', Text );
Alert (alertmsg );
} Else if (prompt ('Press Ctrl + C Copy to clipboard', text )){
Alert (alertmsg );
}
}

Function isUndefined (variable ){
Return typeof variable = 'undefined '? True: false;
}

Function mb_strlen (str ){
Var len = 0;
For (var I = 0; I <str. length; I ++ ){
Len + = str. charCodeAt (I)