console 命令行工具 X clear

console

//单向选择
var a=3;
if(a=3){
    document.write("True!"+'</br>');
}


//双向选择
var b=3;
if(b=3){
    document.write("True!"+'</br>');
}else{
    document.write("False!"+'</br>');
}


//多向选择
var c=2;
if(c<3){
    document.write("False!"+'</br>');
}else if(c=2){
    document.write("True!"+'</br>');
}else{
    document.write("False!!"+'</br>');
}


//嵌套
var score=90;
if(score>=60){
    if(score>=80){
        document.write("Excellent!"+'</br>');
    }else{
        document.write("Pass"+'</br>');
    }
}else{
    if(score<60){
        document.write("Fail!"+'</br>');
    }else{
        document.write("Pass"+'</br>');
    }
}

function isInteger(num){
    var result=false;
    //判断数是否是整数
    result=(parseInt(num)==parseFloat(num))
    return result;
}
var num=15;
//判断15是否是整数
if(isInteger(num)){
    document.write("15 is an integer."+'</br>');
}else{
    document.write(num+"is not an integer."+'</br>');
}

num=15.15;
//判断15.15是否是小数
if(isInteger(num)){
    document.write(num+"is an integer."+'</br>');
}else{
    document.write(num+"is not an integer."+'</br>');
}

//水仙花数
function daffodilNum(){
    document.write("Print daffodil number:"+'</br>');
    for(var num=100;num<1000;num++){
        var unitsDigit=num%10;
        var tensDigit=parseInt((num/10)%10);
        var hundredsDigit=parseInt(num/100);
        if (num == (unitsDigit * unitsDigit * unitsDigit + tensDigit * tensDigit * tensDigit + hundredsDigit * hundredsDigit * hundredsDigit)) {
                //如果是水仙花数，则打印
                document.write("水仙花数有：" + num+'</br>');
            }
    }
}
daffodilNum();

//小数decimal的判断
function isDecimal(num2){
    var result=false;
    //判断数是否是小数
    result=(parseInt(num)!=parseFloat(num))
    return result;
}
var num2=3.14;
//判断3.14是否是小数
if(isDecimal(num2)){
    document.write("3.14 is an decimal."+'</br>');
}else{
    document.write(num2+"is not an decimal."+'</br>');
}

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