Console command to make JS debugging easier

I. Commands to display information

Console.log ("normal");           // used to output general information Console. Info ("Information");     // used to output the console of informational information. Error ("error");          // used to output error message console. warn ("Warn");            // for output warning messages

Second, Dot: character (%s), Integer (%d or%i), floating-point number (%f), and Object (%o);

Console.log ("%s", "string");                 // character (%s)Console.log ("%d%d months%d days", 2016,8,29);       // Integer (%d or%i)console.log ("Pi is%f", 3.1415926);         // floating point (%f) var dog == "Da Mao" = "Yellow" = "female Dog"; Console.log ("%o", dog);                      // object (%o)

Third, Information Group (Console.group (), Console.groupend ())

Console.group ("First set of Information");    Console.log ("First Group first: my Blog");    Console.log ("First Group II: CSDN"); Console.groupend (); Console.group ("Second set of Information");    Console.log ("The second group first: program enthusiasts QQ Group");    Console.log ("second group II: welcome you to join"); Console.groupend ();

Iv. displaying objects in a tree-like structure (Console.dir () can display all properties and methods of an object)

var info = {    "Alan"    ,    "I", "nothing"    ,function  () {        returnthis. Name;    }} Console.dir (info);

V. Display the contents of a node (Console.dirxml () to display the Html/xml code contained in a node of a Web page)

var node = document.getElementById ("info"+ = "<p> added element display </p>"; Console.dirxml ( node);

Six, determine whether the variable is true (Console.assert () is used to determine whether an expression or variable is true, only the expression is false, output a corresponding rest, and throw an exception)

var false  ' only output when Testobj is False! ‘);

Seven, chronograph function (Console.time () and Console.timeend (), used to display the code run time)

Console.time ("console Timer");  for (var i = 0; i < 10000; i++) {    for (var j = 0; J < 10000; J + +) {}       }conso Le.timeend ("console Timer");

Performance Analysis Performance profile (that is, the analysis of the various parts of the running time, to find out the bottleneck, using the method is Console.profile () and console.proileend ();)

functionAll () {//alert (one);     for(vari = 0; I < 10; i++) {Funca (100); } FUNCB (1000);}functionFunca (count) { for(vari = 0; I < count; i++){};}functionFUNCB (count) { for(vari = 0; I < count; i++){};} Console.profile ("Performance Analyzer"); All (); Console.profileend ();

Detailed information is viewed in the "Profile" tab of the Chrome console

Ix. Console.count () Number of times the code was executed

function myFunction () {    console.count ("number of MyFunction executed");} MyFunction ();        // number of MyFunction executed: 1myFunction ();       // number of MyFunction executed: 2myFunction ();       // number of MyFunction executed: 3

X. Keys and values, to be entered in the browser

Xi. console.table Table Display method

var mytable = [    {        "Alan",        "man"        , "+"    },    {        "Wu",        "Gril",        "i"    },    {        "Tao",         "Man and Gril",        "}]console.table"    (mytable);

12. The Chrome console natively supports jquery-like selectors, meaning you can select the DOM section with $ plus a familiar CSS selector.

$ ("body");           // Select Body Node

13. Copy copies the contents obtained from the console to the Clipboard by this command

copy (document.body);                      Copy bodycopy (document.getElementById ("info"));    Copy the node of an ID element

14. The $_ command returns the results of the most recent expression execution, $0-$4 represents the last 5 DOM nodes you have selected

XV, using the console output text, pictures, with the beginning of%c, the following text on the printed information, the next parameter is the style attributes;

Console.log ("Please specify in the email%c from: Console", "Font-size:16px;color:red;font-weight:bold;");

Console command to make JS debugging easier