SOURCE

console 命令行工具 X clear

                    
>
console
function writeDocument(variable) {
    document.write(variable + "<br/>");
}


var sy="I am a student";
var syy=sy.replace(/\s*/g,"");
var sum=0;
for(var i of sy){
    sum++;
}
writeDocument("字符串长度为:"+sum);
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
    </script>
</head>
<body>
</body>
</html>