console 命令行工具 X clear
console
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
        
        function getwordnum(str)
            {
                var num=1;
                for(var i=0;i<str.length;i++)
                {
                    var char=str.charAt(i);
                    if (char ==" "){
                        num++;}
                }

            return num;    
            }

     document.write(getwordnum("Rome was not built in a day")+"</br>"); 
    
    //替换字符
    var str="Hello,Lvye!"
    var str_new= str.replace(/e/g,"");

     document.write(str_new); 
     

    </script>
</head>
<body>
</body>
</html>