<! DOCTYPE html>window.onload=function() {showTime (); }; functionChecktime (i) {//fill-in processing if(i<10) {i= "0" +i; } Else{returni;} } functionShowTime () {varnow=NewDate (); varYear=now.getfullyear (); varMonth=Now.getmonth (); varday=now.getdate (); varH=now.gethours (); varm=now.getminutes (); vars=now.getseconds (); M=Checktime (m); S=Checktime (s); varweekday=NewArray (7); weekday[0]= "Sunday"; weekday[1]= "Monday"; weekday[2]= "Tuesday"; weekday[3]= "Wednesday"; weekday[4]= "Thursday"; weekday[5]= "Friday"; weekday[6]= "Saturday"; document.getElementById ("Show"). Innerhtml= "+year+" year "+month+" month "+day+" Day "+weekday[now.getday ()]+h+": "+m+": "+s; T=settimeout (' ShowTime () ', 1000); /*t=settimeout (showtime,1000); Yes, same effect.*/ /*t=settimeout (ShowTime (), 1000); No, call the result of the function directly (that is, a fixed value), run out of the result at the beginning and assign the value to T, equivalent to T=settimeout (time to run the program, +)*/ }</script>JS Call function when the parentheses add to the difference, function () &function