Javascript notes and summaries (2-13) Timers SetTimeout and SetInterval

The timer allows the JS effect to execute once every few seconds or after n seconds to perform an effect. Timers do not belong to JavaScript, and are features provided by the Window object.

SetTimeout usage:

Window.settimeout (' statement ', MS);   // executes a statement after a specified millisecond

Cases

<! DOCTYPE html>        #div1 {            width:300px;            height:300px;            Background:blue;            Border-bottom:1px solid black;        }     </style> function Change () {            document.getElementById ("P"). InnerHTML = "replaced";        }        Window.settimeout (//3 seconds to execute change method    </script>    </body></ Html>      

Optimization: Timer effect plus countdown effect

SetInterval (' statement ', MS);  Execute once every specified millisecond

To clear the timer:

Clearinterval (); and cleartimeout ();

Code

<!     DOCTYPE html>#div1 {width:300px;            height:300px;            Background:blue; Border-bottom:1px solid black; }    </style>functionChange () {varINP = Document.getelementsbyname ("Time") [0]; varTime = parseint (inp.value)-1; Inp.value=Time ; if(Time = = 0) {document.getElementById ("P"). InnerHTML = "replaced";  Clearinterval (clock);        //Clear Timer } }        varClock = setinterval ("Change ()", 1000);//executes once per second</script> </body>
"Example" if setinterval is not applicable, use only setTimeout to achieve the effect of performing once every time
Using SetTimeout to achieve setinterval effects
<!     DOCTYPE html>#div1 {width:300px;            height:300px;            Background:blue; Border-bottom:1px solid black; }    </style>varClock =NULL; functionChange () {varINP = Document.getelementsbyname ("Time") [0]; varTime = parseint (inp.value)-1; Inp.value=Time ; if(Time = = 0) {document.getElementById ("P"). InnerHTML = "replaced";                Cleartimeout (clock); return; } setTimeout ( "Change ()",); }        varClock = setTimeout ("Change ()", 1000);//executes once per second</script> </body>
Javascript notes and summaries (2-13) Timers SetTimeout and SetInterval