课程 \
JavaScript进阶篇
4-6 反反复复(while循环)
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>while</title>
<script type="text/javascript">
var mynum =1;//mynum初值化数值为1
while(mynum<=5)
{
document.write("数字:"+mynum);
mynum=mynum+1;
}
</script>
</head>
<body>
</body>
</html>
2017-11-21
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4-5 重复重复（for循环）
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>if...else</title>
<script type="text/JavaScript">
var mymoney,sum=0;//mymoney变量存放不同面值，sum总计
for(mymoney=1;mymoney<=10;mymoney++)
{
sum= sum + mymoney;
}
document.write("sum合计:"+sum);
</script>
</head>
<body>
</body>
</html>
2017-11-21
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4-4 多种选择（Switch语句)
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>switch</title>
<script type="text/JavaScript">
var myweek =3;//myweek表示星期几变量
switch(myweek)
{
case 1:
case 2:
document.write("学习理念知识");
break;
case 3:
case 4:
document.write("到企业实践");
break;
case 5:
document.write("总结经验");
case 6:
case 7:
document.write("周六、日休息和娱乐");
break;
default:
document.write("不存在的！")；
}
</script>
</head>
<body>
</body>
</html>
2017-11-21
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4-3 多重判断（if..else嵌套语句）
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>if...else</title>
<script type="text/JavaScript">
var myage =99;//赵红的年龄为99
if(myage<=44)
{document.write("青年");}
else if(myage<=59)
{document.write("中年人");}
else if (myage<=89)
{document.write("老年人");}
else
{document.write("长寿老年人");}
</script>
</head>
<body>
</body>
</html>
2017-11-21
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4-2 二选一 （if...else语句）
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>if...else</title>
<script type="text/JavaScript">
var ticket =true; //ticket初值为true，表示有票
if(ticket)
{
document.write("有票，可以看电影。");
}
else
{
document.write("没票，电影看不成。");
}
</script>
</head>
<body>
</body>
</html>
2017-11-21
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4-1 做判断（if语句）
<!DOCTYPE HTML>
<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>if语句</title>
<script type="text/JavaScript">
var mypen = "black"; //定义变量mypen，存储笔的黑色。
if(mypen="black")
{
document.write("笔是黑色的，所以购买");
}
</script>
</head>
<body>
</body>
</html>
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2-13 编程练习
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS基础</title>
<script type="text/javascript">
var a,b,sum;
var a = 5;
var b = 100%7;
sum = a > b && a*b > 0 ;
document.write( "我认为 a 的值是:" + ? + " b的值是:" + ? + "sum 的值是:" + ?+"<br/>");
document.write( "答案是,第一轮计算后，a 为："+ a +";b为："+b +";第一次计算sum为："+ sum +"<br/>");
sum = ( (++a) + 3 ) / (2 - (--b) ) * 3;
document.write( "再一次计算后，我认为 a 的值是:" + ? + " b的值是:" + ? + "sum 的值是:" + ? +"<br/>");
document.write( "答案是，第二轮计算后，a 为：" + a + ";b为：" + b +";第二次计算sum为："+ sum +",sum的类型也发生变化了。");
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-11 是非颠倒(逻辑非操作符）
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>逻辑非</title>
<script type="text/javascript">
var numa,numb,jq1;
numa=60;
numb=70;
jq1= !(numa<numb) ;
document.write("jq1的值是:"+jq1+"<br>")
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-10 我或你都可以 (逻辑或操作符）
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>逻辑或</title>
<script type="text/javascript">
var numa,numb,jq1;
numa=50;
numb=55;
jq1= numa>numb||numa==numb ;
document.write("jq1的值是:"+jq1+"<br>")
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-9 我与你同在(逻辑与操作符）
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>逻辑与</title>
<script type="text/javascript">
var numa,numb;
numa=60;
numb=70;
if(numa>=60&&numb>=60 )
{
document.write("JavaScript考核通过！"+"<br>");
}
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-8 较量较量(比较操作符)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>比较操作符</title>
<script type="text/javascript">
var numa,numb,jq1,jq2;
numa=1;
numb=7;
jq1=numa>numb ;
jq2=numa!=numb ;
document.write("numa大于numb的分数吗？"+jq1+"<br>")
document.write("numa不等于numb的分数吗？"+ jq2);
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-7 自加一，自减一 ( ++和- -)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>++/--</title>
<script type="text/javascript">
var numa=1;
var numb=7;
numa++;
numb--;
document.write("numa的值:"+numa);
document.write("numb的值:"+numb);
</script>
</head>
<body>
</body>
</html>
2017-11-21
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2-6 我还有其它用途( +号操作符）
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>+操作符</title>
<script type="text/javascript">
var mynum= 1+5 ;
var mychar= "中"+"国" ;
document.write("mynum的值:"+mynum+"<br>");
document.write("mychar的值:"+mychar);
</script>
</head>
<body>
</body>
</html>
2017-11-21
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