流程控制

条件语句

if 语句

// if 判断
var exp = true;
if (exp) {
	document.write("exp is true");
}
if (exp) {
	document.write("exp is true");
} else {
	document.write("exp is false");
}

switch 语句

// switch 判断使用 === 进行比较
var index = 1;
switch (index) {
	case 0:
		document.write("index is 0");
		break;
	case 1:
		document.write("index is number 1");
		break;
	case "1":
		document.write("index is string 1");
		break;
	default:
		document.write("index default");
		break;
}

循环语句

for 循环

for (var i = 0; i < 10; i++) {
	document.write("index = " + i);
	document.write("<br />");
}

while 循环

var index = 5;
while (index > 0) {
	document.write("index = " + index);
	document.write("<br />");
	index--;
}

do while 循环

var index = 1;
do {
	document.write("do action");
	document.write("<br />");
	index++;
} while (index < 0)

continue/break

continue 跳出当前循环条件

for (var i = 0; i < 10; i++) {
	if (i == 5) {
        // 仅跳过等于5的条件
		continue;
	}
	document.write("index = " + i);
	document.write("<br />");
}

break 跳出当前循环体

for (var i = 0; i < 10; i++) {
	if (i == 5) {
        // 当条件等于5时跳出循环体
		break;
	}
	document.write("index = " + i);
	document.write("<br />");
}