Detailed answers to js basic syntax

Several common basic simple judgments in js, detailed answers to loop syntax

1.if statement

if (条件 1)
  {
  当条件 1 为 true 时执行的代码
  }
else if (条件 2)
  {
  当条件 2 为 true 时执行的代码
  }
else
  {
  当条件 1 和 条件 2 都不为 true 时执行的代码
  }

2. Switch statement

switch(n)
{
case 1:
  执行代码块 1
  break;
case 2:
  执行代码块 2
  break;
default:
  n 与 case 1 和 case 2 不同时执行的代码
}

3. While statement

格式：while (条件){
  需要执行的代码
 }

4. Do while statement

格式:do
  {
  需要执行的代码
  }
while (条件);
如下：
do
  {
  x=x + "打印的数字是 " + i + "<br>";
  i++;
  }
while (i<8);

5. For statement

格式:for (赋值;逻辑判断;运算){
        //循环体
}
如：for (var i=0;i<100;i++)
{
document.write(100 + "<br>");
}

6. this

<script type="text/javascript">
alert(this==window);
</script>

The pop-up box displays: true.

It can be seen that this is the current window.

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

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