<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<script type="text/javascript">
//条件语句
if(3>11)
document.write('hello ');
document.write('world');
document.write('<hr color="red"/>');
if(false){
document.write('hello ');
document.write('King');
var x=1,y=2,username='king';
}
document.write(x+'--'+y+'--'+username);
//if ... else
document.write('<hr color="darkred"/>');
var username='king1';
if(username=='king'){
document.write('hello king');
}else{
document.write('hello maizi');
}
document.write('<hr color="red"/>');
//if esle if
username='admin';
if(username=='king'){
document.write('hello king');
}else if(username=='maizi'){
document.write('hello maizi');
}else if(username=='admin'){
document.write('hello admin');
}
document.write('<hr color="red"/>');
if(true==false){
document.write('a');
}else if(3>11){
document.write('b');
}
document.write('<hr color="red"/>');
var x=11;
if(x==1){
document.write('aaa');
}else if(x==2){
document.write('bbb');
}else if(x==3){
document.write('ccc');
}else{
document.write('以上表达式都为false执行的代码段');
}
document.write('<hr color="aqua"/>');
//switch...case语句
/*
switch(exp){
case 值1:
执行的代码段;
break;
case 值2:
执行的代码段;
break;
...
default:
执行的代码段;
break;
严格类型比较
}
*/
var i=1;
var i=true;
switch(i){
case '1':
document.write('king');
break;
case 1:
document.write('aa');
break;
case 2:
document.write('bb');
break;
default:
document.write('以上case都没有匹配到的时候执行的代码段');
break;
case 3:
document.write('cc');
break;
case 4:
document.write('dd');
break;
}
document.write('<br/>continue...');
document.write('<hr color="red"/>');
i=14;
switch(i){
case 1:
document.write('a');
case 2:
document.write('b');
default:
document.write('e');
case 3:
document.write('c');
break;
case 4:
document.write('d');
}
document.write('<hr color="red"/>');
var i=66;
switch(i){
case 1:
case 2:
case 3:
document.write('hello king');
break;
case 4:
case 5:
case 6:
document.write('hello maizi');
break;
default:
document.write('hello everybody');
break;
}
</script>
</body>
</html>