console 命令行工具 X clear

console

//作业一：判断字符串的长度
function howlong (strname)
{
    var num=0;
    var number01=strname.split(""); //切割字符串
    document.write(number01+ "<br/>");
    document.write(typeof(number01)+ "<br/>");//判断number01的类型
    for(var i=0;i<number01.length;i++)
    {
        if(typeof(strname[i])=='string')
        {
            num++;
            //document.write(strname[i]+ "<br/>");
        }
    }
    return num;
}



var name="Rome was not built in a day";
var a=howlong(name);
document.write("该字符串的个数为："+a+ "<br/>");
//document.write(typeof(name)+ "<br/>");
//document.write(name.length+ "<br/>");


//作业二：将字符串的顺序颠倒
var test="asdfghj";
function back (tr)
{
    var temp=[];
    for(var i=0;i<tr.length;i++)
    {
        temp[i]=tr[tr.length-i-1];
    }
    var tr1=temp.join("");
    return tr1;
}
var b=back(test);
document.write("原来的排列:"+test+ "<br/>");
document.write("顺序颠倒后的排列："+b+ "<br/>");



//作业三：循环算出1+2+3+4....+100=的值
//方法一：
var n = 1;
var sum = 0;
//如果n小于等于100，则会执行while循环
while (n <= 100)
{
    sum=sum+n;
    n=n+1;
}
document.write("1+2+3+…+100 = " + sum+ "<br/>");

//方法二：
var n = 1;
var sum = 0;
do
{
    sum += n;
    n++;
}while (n <= 100);
document.write("1+2+3+…+100 = " + sum+ "<br/>");


//方法三：
var sum = 0;
for(var i=1;i<=100;i++)
{
    sum=sum+i;
}
document.write("1+2+3+…+100 = " + sum+ "<br/>");

<!DOCTYPE html> 
<html>
<head>
<meta charset="utf-8" />
<script>
    
</script>
</head>
<body>
<script>
</script>
</body>
</html>