Collection of basic knowledge of javascript (2) Recommended collection

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Collection of basic knowledge of javascript (2) Recommended collection_Basic knowledge

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May 16, 2016 pm 06:11 PM

javascript basic knowledge

Look at the attached example in detail, it is relatively simple to write.

1. About cookie functions:

Copy code The code is as follows :

 
/**
* Cookie operation tool. 
* Usage method: Save value: CookieTool('name','1',{expires: 7}) //Indicates saving a cookie with a value of 1 and a key value of name, which is invalid. Time 7 days later
* Value: CookieTool('name') //Return 1 
* @param {} name 
* @param {} value 
* @param {} options 
* @return {} 
*/ 
CookieTool = function(name, value, options) { 
if (typeof value != 'undefined') { 
options = options || {}; 
if (value === null) { 
value = ''; 
options.expires = -1; 
} 
var expires = ''; 
if (options.expires && (typeof options.expires == 'number' || options.expires.toUTCString)) { 
var date; 
if (typeof options.expires == 'number') { 
date = new Date(); 
date.setTime(date.getTime() (options.expires * 24 * 60 * 60 * 1000)); 
} else { 
date = options .expires; 
} 
expires = '; expires=' date.toUTCString(); 
} 
var path = options.path ? '; path=' (options.path) : '' ; 
var domain = options.domain ? '; domain=' (options.domain) : ''; 
var secure = options.secure ? '; secure' : ''; 
document.cookie = [name, '=', encodeURIComponent(value), expires, path, domain, secure].join(''); 
} else { 
var cookieValue = null; 
if (document.cookie && document.cookie != '') { 
var cookies = document.cookie.split(';'); 
for (var i = 0; i < cookies.length; i ) { 
var cookie = trim(cookies[i]); 
if (cookie.substring(0, name.length 1) == (name '=')) { 
cookieValue = decodeURIComponent(cookie.substring(name.length 1)); 
break; 
} 
} 
} 
return cookieValue; 
} 
}; 

2. Regarding a js function that can view js objects, a cool method:

Copy the code The code is as follows:

/**
* Used to view the properties of an object
*/
function debugObjectInfo(obj){
traceObject(obj);

function traceObject(obj){
var str = ' ';
if(obj.tagName&&obj.name&&obj.id)
str="

else{
str="";
}
var key=[];
for(var i in obj ){
key.push(i);
}
key.sort();
for(var i=0;ivar v= new String(obj[key[i]]).replace(//g,">");
str ="";
}
str=str "

" key[i] "

" v "

";
writeMsg(str);
}
function trace(v){
var str="

";
str =String(v).replace(//g ,">");
str ="

";
writeMsg(str);
}
function writeMsg(s) {
traceWin=window.open("","traceWindow","height=600, width=800,scrollbars=yes");
traceWin.document.write(s);
}
}

3. Regular expression:

g represents global matching
m represents multi-line matching
i represents case-insensitive matching
^ matching The start position of the input string
$ matches the end position of the input string
* matches the previous subexpression zero or more times. Equivalent to {0,}
matches the previous subexpression once or more times. Equivalent to {1,}
? Matches the preceding subexpression zero or one time. Equivalent to [0,1} when this character is followed by any other qualifier (*, , ? , {n}, {n,}, {n,m}) later, the matching pattern is non-greedy. Non-greedy mode matches as little of the searched string as possible, while the default greedy mode matches as much of the searched string as possible. For example, for the string "oooo", 'o ?' will match a single "o", while 'o ' will match all 'o's.

d matches a numeric character. Equivalent to [0-9]
D matches a non-numeric character. Equivalent to [^0-9]
w, equivalent to "[A -Za-z0-9_]"
W matches any non-word character, equivalent to "[^A-Za-z0-9]"
s matches any whitespace character, including spaces, tabs, and formfeeds Etc. Equivalent to [fnrtv]
S matches any non-whitespace character. Equivalent to [^frntv]
b matches a word boundary, that is, the position between a word and a space.
B matches non-word boundaries.

Common js methods for regular expressions: