当外循环i=5时,
内循环从j=0 ---j=4都是执行的,但是当j=5时,内循环终止了,以及后边的j=6,7,8,9都不再执行;紧接着继续外循环i=6,继续内循环
var firstday = 3, lastday = 5, nday = 19for (var m = 0 m < firstday m++) {
document.write("<td>1</td>")
}
var nday = 0
for (var j = 0 j < (7 - firstday) j++) {
if (nday > lastday) {
break
} else {
document.write("<td>" + nday + "</td>")
}
nday += 1
}