javascript round to 2 decimal

--------------- Original article from javaScript advanced programming -----------------------Complex Mode-group:[Javascript]/*** Group,* Assume that you want to match the string "dogdog ". Use current knowledge* Possible estimation expressions should be similar:*/Var res =/dogdog/g;Alert (res. test ("dogdog "));// Rewrite the group:Var res =/(dog) {2}/g;Alert (re

From: http://student.csdn.net/space.php? Uid = 45106 Do = Blog view = me Chapter 2 Some of the essential JavaScript features bring much more trouble than they do. Some of these features may cause portability problems due to imperfect specifications. Some features may cause problems that are hard to understand and modify. Code Some features make my code style too complex and error-prone; some features a

\u4e16\u754c" = = = "Hello, world" //= = TrueCommentsComments like Java and C, multi-line comments cannot be nested//single line,/* */multiple lines;Direct volumeDirect volume (literal) is the data value that is used directly in the program1 2// number 1.2 //decimal number 3' hello ' //String 4True //Boolean True 5 false //Boolean false 6 /

Javascript Object Data1 FunctionFunction add (I, j ){}Var fun = function (){}2 ObjectJSONVar students = {Name: "suns ",Age: 10GetName: function (){}};3 ArrayArray features:Var array = ["suns", 10];Array. length;Push ();Pop ();Shift ();Unshift ();Reverse ();Sort ();Join ("-d -");-----------------------------------------StringVar name = "suns ";Var name = new String ("suns ");Java judges that the string conte

Javascript Object Data 1 Functionfunctionadd (I, j) {} varfunfunction () {} 2 ObjectJSONvarstudents {name: quot; suns quot;, age: 10 getName: function () {}}; 3Array number... Javascript Object Data1 FunctionFunction add (I, j ){}Var fun = function (){}2 ObjectJSONVar students = {Name: "suns ",Age: 10GetName: functio

, except for the left 1 of the decimal point), exponent 4 (binary shift code 00000000010), sign bit 0 = = Computer Storage: 0 00000000100 10011001100110011 ... 11001 = = Because the mantissa is up to 52 bits, the actual stored value is 0.00011001100110011001100110011001100110011001100110011001 and the decimal 0.2 = = Binary 0.0011001100110011 ... (Cycle 0011) = = Mantissa is 1.1001100110011001100 ... 1

Using this program can achieve many common animation effects, including size transformation, position transformation, fade fade and so on. Program Description: The principle of the gradient effect is to use the timer constantly set the value, if you want to slow down the effect of setting a step (detailed look at JavaScript spring effect). This is just a combination of the properties that can be changed (transparency, width, height, left and top), wit

variables [coercion] variables and functions must be defined before they are used.// goodvar name = ‘MyName‘;// badname = ‘MyName‘;[Force] Only one variable can be declared per var.Explain:A var declares multiple variables, which can lead to a longer length of the head and can easily confuse commas and semicolons when modified.// goodvar hangModules = [];var missModules = [];var visited = {};// badvar hangModules = [], missModules = [], visited = {};The [force] variable must be declared as

: indicates the date object.Regexp class: the regular expression object.Error class: an object with an error in Js. 8. Note the following when using data types:1): Number:What are the octal, decimal, and hexadecimal numbers...Octal: var num = 011; // starts with "0"Hexadecimal: var num = 0x1f; // It starts with "0x"Therefore, attention must be paid to Javascript, a language that can be recognized.Alert (3

1. Don't make any assumptions (JavaScript is an unreliable helper) One of the most important features of a potentially unobtrusive JavaScript is that you want to stop any assumption: * Don't assume that JavaScript is available, you'd better think it's probably not useful, not directly dependent on it. * Do not assume that browsers support them before you test to

1. Strict mode: A different parsing and execution model is defined in JavaScript. In strict mode, some indeterminate behavior will be handled, and some unsafe operations will throw an error.Usage is added in the script: "Usestrict";This is a compilation instruction that tells the engine to switch to strict mode;2, the statement in JavaScript, if not with a semico

array or an object in a tablePlease click here to enter the picture descriptionChrome Users Note that table () is not working, and you can solve this problem by putting the item in an array or object.Console.table ([[' JavaScript ', ' php ', ' Java ']]);4, Console.group (); Consisting of at least 3 console calls, it outputs multiple levels, showing the following effects:Please click here to enter the picture description5, Console.time (ID) and consol

Chapter 2 Essence Some of the features of JavaScript bring much more trouble than they do. Some of these features may cause portability problems due to imperfect specifications. Some features may generate codes that are hard to understand and modify; some features make my code style too complex and error-prone; others are design errors. Sometimes Language designers make mistakes.Most programming languages h

operations between variables and/or values.JavaScript Assignment operatorsAssignment operators are used to assign values to JavaScript variables.The + operator for stringsThe + operator is used to add a literal value or a string variable (to join together).adding arithmetic to strings and numbersIf you add a number to a string, the result becomes a string.************************************Given y=5, these arithmetic operators are explained in the f

parent context of other variable objects, k: 3}, _ activity object AO: {x: 1}] In the helper context; data [2]. [[Scope] = [... // activity object AO: {data: [...] in the parent context of other variable objects, k: 3}, _ activity object AO: {x: 2}] In the helper context;We can see that the [[Scope] attribute of the function has the desired value. To achieve this purpose, we have to create additional varia

JavaScript data Types A string (string), a number, a Boolean (Boolean), an array, an object (objects), null (NULL), undefined (Undefined ). Eg:var variable_name= "JavaScript Everyday Learning 2"//Stringvar variable_name=3.14//decimal var variable_name=3//Integervar variable_name=true//Boolean (FALSE)var variable_name

JavaScript exploration: Constructor JavaScript probing: executable context Stack Execution context 1: Variable object and activity object Execution context 2: Scope chain Scope Chains Execution context 3: Closure Closures Execution context 4: This pointer Exploring JavaScript: Powerful prototype and prototype c

What is 1,javascript?is a scripting language that requires a host file, and its host file is an HTML file.2, what does it have to do with Java?There is no direct relationship, Java is Sun (acquired by Oracle),Netspace (Netscape, US online acquisition), JScript is Microsoft's,Similar to Java 90%, but some of the features are only available on IE.3, its usage:There are three blocks in the HTML position:①head

is delivered by the server and loaded by the browser, the client script allows users to interact with the webpage. For example, Google Maps uses JavaScript to support interaction between users and Maps. The interaction methods include moving Maps, enlarging and narrowing down. Without the JavaScript language, the webpage needs to refresh the interaction behavior with each user each time, unless the page us

Function object: the number of the length parameter, prototype, which cannot be enumeratedMethods of functions apply and call, using the method of one object to another objectBind ()Boolean and numeric type and string typeOverriding the ToString method, toLocaleString, ValueOf, the boolean of the base type and the reference type are very different, preferably not with a Boolean of reference typeNumber also overrides three methods, the first returns the value of the string, the third returns the