原生JavaScript运算符与流程控制详解

window.onload = function(){
 alert(0%2) //0
 alert(1%2) //1
 alert(2%2) //0
}

<body>
 <ol>
  <li>取模：就是求余数</li>
  <li></li>
  <li></li>
 </ol>
 <script>
  window.onload = function(){
   var aLi = document.getElementsByTagName('li');
   for(var i = 0; i < aLi.length; i++){
    if(i % 2 == 0){
     aLi[i].style.background = 'red'
    }else{
     aLi[i].style.background = 'green'
    }
   }
  }
 </script>
</body>

<script>
 window.onload = function () {
  var a = 1568
  console.log(parseInt(a / 60) + '分' + a % 60 + '秒')
 }
</script>

a = a + 1;
a+=1
a++

<script>
 window.onload = function () {
  var name = 'abc';
  var sex = ''
  switch (sex) {
   case '男':
    alert(name + '先生，你好');
    break;
   case '女':
    alert(name + '女士，你好');
    break;
   default:
    alert(name + '你好')
  }
 }
</script>

window.onload = function(){
 for(var i = 0; i < 5; i++){
  if(i == 3){
   //break; //整个循环中断了
   continue; //本次循环中断了
  }
  alert(i)
 }
}

window.onload = function(){
 //真：true、非0数值、非空字符串('false'或‘ ')、非空对象
 //假: false、数值0、空字符串、空对象(null)、undefined
 var a = 'false'
 if(a){
  alert('真的')
 }else{
  alert('假的')
 }
}