JavaScript Learning 4

one, Array Object

Arrayobject.reverse () flips the array

Arrayobject.shift () Deletes the first element in the array and returns it

Arrayobject.unshift ( element 1, element 2) adds one or more array elements to the beginning of the array and returns the length of the new array

Arrayobject.pop () Deletes the last element of the array and returns it

Arrayobject.push () adds one or more array elements to the end of the array and returns the new length

Arrayobject.sort (sortby) Sorting an array element

second, Date Object

first: use the new keyword with date () to create a parameter with (return a specified time and Date)

second: use the new keyword with date () to create without parameters (returns the current specified Date)

Date Method Instance<script type= "text/javascript" >//Create a time Date object        varToday =NewDate (); //gets the 4-digit year from this object        varYear =Today.getfullyear (); varm = Today.getmonth () +1; vart =today.getdate (); varxs =today.gethours (); varFZ =today.getminutes (); varms =Today.getseconds (); varHMS =Today.getmilliseconds (); varSJC =Today.gettime (); //defines a string to output        varstr = "; STR+ = "this Year is:" +year ; STR+ = "<br/> Month is:" +I (m); STR+ = "<br/> Today is:" +I (t); STR+ = "<br/> Current hour:" +I (xs); STR+ = "<br/> Current minute:" +I (fz); STR+ = "<br/> Current number of seconds:" +I (ms); STR+ = "<br/> Current millisecond:" +I (hms); STR+ = "<br/> Current timestamp:" +SJC document.write (str); //Leading 0        functionI (y) {returny<10? "0" +y:y; }    </script>

third, the Math Object

The Math object does not need to be created for direct use .

Math.Abs (x) to find the absolute value of x

Math.ceil (x) Upward rounding of X

Math.floor (x) to perform a downward rounding of X

Math.max (n1,n2,n3) Returns the maximum number

Math.min (n1,n2,n3) Returns the smallest number

Math.sqrt (x) returns the square root of x

Math.pow (x, y) returns the x- Square

Math.Round (x) rounding x

Math.random () returns a random number between 0~1 contains 0 but does not contain 1[0,1]

<script type= "text/javascript" >        // ask for a random number  to encapsulate it into  a function        //  This function needs to have two values  one is the maximum one is the minimum        function  getrandom (a, b)                        {return Math.floor (math.random () * (a-b+1) +b);                        }         //         document.write (getrandom (20,10));     </script>

Iv. Methods for Window objects

Window.alert () pops a warning prompt to the Browser's window

Window.prompt () pops an input dialog box into the Browser's window

Window.confirm () pops up a confirmation dialog to the browser window and clicks The "ok" button to get the boolean true, and clicking the "cancel" button will give the Boolean type false

window.open (url,name,options) opens a new window

Window.close () to close the current window

Window.settimeout (CODE,MILLISEC) timer: executes code once the specified time is up. code: Execution of the JS code, millisec: number of milliseconds

Window.cleartimeout ( to clear the return value of the delay ) clears the timer

Window.setinterval (CODE,MILLISEC) timer: executes code code at every time

Window.clearinterval ( the Timer return value to clear ) clears the timer

Dynamic Clock:<style type= "text/css" >div{width:400px;            height:200px; line-height:200px; Text-align:center;            background:skyblue;        margin:100px auto; }    </style> <script type= "text/javascript" >functionGetweek (week) {varstr = "week"; Switch(week) { case1: Str+ = "one";  break;  case2: Str+ = "two";  break;  case3: Str+ = "three";  break;  case4: Str+ = "four";  break;  case5: Str+ = "five";  break;  case6: Str+ = "six";  break; default: Str+ = "day";  break; }            returnstr; }        functionI (y) {returny<10? "0" +y:y; }        //every second to update a time every second to get back to the time        functiongetclock () {//Create a time Date object            varToday =NewDate (); vary =Today.getfullyear (); varm =Today.getmonth (); varD =today.getdate (); varh =today.gethours (); varf =today.getminutes (); vars =Today.getseconds (); varW =Today.getday (); varstr = y+ "-" + i (m) + "-" +i (d) + "&nbsp;" +i (h) + ":" +i (f) + ":" +i (s) + "&nbsp;" +Getweek (w); //You need to write to the div to get the HTML tag before you write it.document.getElementById ("div"). InnerHTML =str; }        //after the page is loaded, execute the code inside.Window.onload =function(){            //every second to use the timer every second to request Getclock () The function of this function will be every second to get the system timeSetInterval ("getclock ()", 1000); }    </script>
JavaScript Learning 4