Loop control
while 和 for
<! DOCTYPE HTML> <HTML lang = " EN " > <head> <Meta charset = " UTF-. 8 " > <title> cycle control </ title> </ head> <body> <Script type = " text / JavaScript " > // the while three elements: the initial variables are updated determination condition variable var NUM = . 1 , SUM = 0 ; the while (NUM <= 100 ) { SUM + = NUM; NUM ++ ; } the console.log (SUM); //and while the difference between do whie is executed once and then the first loop var num2 = . 1 , SUM2 = 0 ; do { SUM2 + = num2; num2 ++ ; } while (num2 <= 100 ); the console.log (SUM2); / / for traversal cycle var sum3 = 0 ; for ( var I = . 1 ; I <= 100 ; I ++ ) { sum3 + = I; } the console.log (sum3); //Output right triangle browser for ( var J = . 1 ; J <= . 6 ; J ++) { // the control of the number of rows for ( var K = . 1 ; K <= J; K ++) { // control * Document. Write ( " * " ); } document.write ( ' <br> ' ); } </ Script> </ body> </ HTML>