function fun(){
    var is = confirm(‘选择对话框‘);/*确定取消对话框*/
    if(is == true){
        document.write(‘真‘);/*网页输出字符*/
    }else{
        document.write(‘假‘);
    }
    
    var name = prompt(‘请输入内容‘,"占位符");
    document.write(name);
}
/*
alert  confrim  ptompt
*/