JavaScript basics -4 JavaScript operators, expressions

First, JavaScript operators

Operator

-Arithmetic operation +-*/% + +--

-Relational Operations > < >= <= = = = = = = =!==

-Logic Operations && | | !

-Bit Arithmetic & | ~ ^ << >> >>>

-Assignment operation = + = = *=/=%=

-Character JOIN Operation +

-Condition (trinocular) operation?:

-Special operator typeof instanceof void Delete

1. Arithmetic arithmetic

Arithmetic operators

-Add (+), subtract (-), multiply (*), divide (/), seek remainder (%)

--can represent a minus sign, or a minus sign, such as: x=-y

-+ can represent addition, can also be used for string connection

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M01/7D/F7/wKiom1bzq9DSNN8CAACMnpY0_-g138.png "title=" Web.png "alt=" Wkiom1bzq9dsnn8caacmnpy0_-g138.png "/>

Using the% operator

-% means to find the remainder operation

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/7D/F3/wKioL1bzrP_RPq-fAADLBzASBWg274.png "title=" Web.png "alt=" Wkiol1bzrp_rpq-faadlbzasbwg274.png "/>

Using the "+ +" and "--" operators

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/7D/F3/wKioL1bzrd2i1BR3AACu23QFhdo856.png "title=" Web.png "alt=" Wkiol1bzrd2i1br3aacu23qfhdo856.png "/>

2. Relational operations

Using relational operators

-relational operations are used to determine the size relationship between data

-">" (Greater Than), "<" (less than), ">=" (greater than or equal), "<=" (less than equals), "= =" (equals), "! =" (Not equal to)

-The value of the relational expression is a Boolean type ("true" or "false")

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M02/7D/F3/wKioL1bzspTCJrtbAACuPRnDzRo186.png "title=" Web.png "alt=" Wkiol1bzsptcjrtbaacuprndzro186.png "/>

-congruent: = = =

-Same type

-Same value

-Not congruent:! ==

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/7D/F7/wKiom1bzsrPQlf4pAADRzY90rqc458.png "title=" Web.png "alt=" Wkiom1bzsrpqlf4paadrzy90rqc458.png "/>

IsNaN function

-IsNaN ()

-Used to determine whether its argument is a "non-numeric (NaN)" Value

-If the result of Nan compared to any value (including itself) is false, then to determine whether a value is Nan, you cannot use the = = or = = = operator, in which case you can only use the isNaN () function

-typically used to detect the operation results of a type conversion function to determine whether they represent a valid number

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M02/7D/F4/wKioL1bztFWyQe6gAAE4J6Gmb_0260.png "title=" Web.png "alt=" Wkiol1bztfwyqe6gaae4j6gmb_0260.png "/>

3. Logical operation

Logical operations

-Logic and (&&), logic or (| |), logical non (!)

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M01/7D/F4/wKioL1bztYKBHLdSAAEFi5ohol4073.png "title=" Web.png "alt=" Wkiol1bztykbhldsaaefi5ohol4073.png "/>

Logic and (&&) operations

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M02/7D/F4/wKioL1bzthvAloMEAAGNwC60LIU709.png "title=" Web.png "alt=" Wkiol1bzthvalomeaagnwc60liu709.png "/>

Logic or (| |) Operation

650) this.width=650; "src=" Http://s4.51cto.com/wyfs02/M00/7D/F7/wKiom1bzteehm3S1AAFoi-QNntc173.png "title=" Web.png "alt=" Wkiom1bzteehm3s1aafoi-qnntc173.png "/>

Logical NON (!) Operation

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M01/7D/F4/wKioL1bztsKBHEG_AAFtoyWYXTk433.png "title=" Web.png "alt=" Wkiol1bztskbheg_aaftoywyxtk433.png "/>

Questions about "Short circuit logic"

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/7D/F7/wKiom1bztmrD5oPuAAFDWi0ImCE723.png "title=" Web.png "alt=" Wkiom1bztmrd5opuaafdwi0imce723.png "/>

4, bit arithmetic

Bit arithmetic

-bitwise operations, which operate on numbers in binary form

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M02/7D/F7/wKiom1bzttiyABQfAABWQGO-Pk4442.png "title=" Web.png "alt=" Wkiom1bzttiyabqfaabwqgo-pk4442.png "/>

5. Assignment operation

Use "=" for assignment operations

-"=" To assign a value to a variable

650) this.width=650; "src=" Http://s2.51cto.com/wyfs02/M00/7D/F4/wKioL1bzt_HRPDMZAACbmbFBmz4577.png "title=" Web.png "alt=" Wkiol1bzt_hrpdmzaacbmbfbmz4577.png "/>

Using an extended assignment expression

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M02/7D/F7/wKiom1bzt67j1leSAAGv1HUXoFY665.png "title=" Web.png "alt=" Wkiom1bzt67j1lesaagv1huxofy665.png "/>

6, character connection operation

Use "+" for string connections

-"+" acts on two numbers, which means arithmetic

-"+" when acting on strings, representing string concatenation operations

650) this.width=650; "src=" Http://s5.51cto.com/wyfs02/M01/7D/F4/wKioL1bzuPjwIcSIAAFv2x9qS9g142.png "title=" Web.png "alt=" Wkiol1bzupjwicsiaafv2x9qs9g142.png "/>

7. Condition (trinocular) operation

Use condition (trinocular) operator

-Three mesh operator (?:) -----need to perform an operation on three expressions

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/7D/F4/wKioL1bzucCROPdpAABAt9_QG54942.png "title=" Web.png "alt=" Wkiol1bzuccropdpaabat9_qg54942.png "/>

Where the value of expression 1 should be a Boolean type, the meaning of the expression:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/7D/F4/wKioL1bzugbAu2UsAAGIVUd90Rs384.png "title=" Web.png "alt=" Wkiol1bzugbau2usaagivud90rs384.png "/>

Use condition (trinocular) operator

-In a conditional operation expression, each expression can be another conditional operation expression, called a nesting of conditional operations

650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M01/7D/F7/wKiom1bzueiyqIXMAAB7737EMCY367.png "title=" Web.png "alt=" Wkiom1bzueiyqixmaab7737emcy367.png "/>

Summary: This chapter focuses on JavaScript operators, expressions

This article from the "Technical Exchange" blog, declined reprint!

JavaScript basics -4 JavaScript operators, expressions