我是javascript的新手，此代码的主要目的是在文本框中键入问题，浏览器将检查该问题是否在switch语句中，并获得答案，而不是将其写在段落的id =“ lable”中。
函数randomArray（z）-line [8]-返回一个随机数组值。
发生什么情况：在具有“标签”作为id的段落上键入：“ undefined”。
.........................
HTML代码：
<body>
<img src="Alexs_face.png">
<p style="border:2px black solid; margin:100px 400px 50px 400px">Ask me !</p>
<p id="lable"></p>
<input id="input" type="text" autocomplete="off">
<input id="send" type="button" onclick="dosome()" value="Send">
<input id="delete" type="button" onclick="deleteVal()" value="Delete"></body>
Javascript：
var greating , userName;
var firstHello = [[greating+userName+", How can I help you ?" ], ["Hi "+userName+" how can i help ?"] ,[ greating+", how can i help ?"]];
dosome () ;
function randomArray (z) {
var index = Math.floor(Math.random() * z.length);
return z[index];
};
function getVal() {
write(randomArray (firstHello)); /* <------ trying to write a radom value from the firstHello array
*/
var ask = document.getElementById("input").value;
return ask ;}
var ask = getVal();
function write (x){
var lable = document.getElementById("lable").innerHTML = x;
return lable ;
};
//Capitalize the first letters func :
function capitalize(string) {
return string.charAt(0).toUpperCase() + string.slice(1);
}
//..............
//............................... you can ignore this function
function dosome () {
var ask = getVal();
var question = ask.split(" ");
var date = new Date().toTimeString().split(" ")[0]; ;
var userName ="Med" ;
//5// give you different "greatings" according to ur time
if (date >= "06:00:00" && date <="11:00:00"){
greating = "Good morning ";
var alertTime=""
}
else if (date >= "11:00:00" && date <= "15:00:00"){
greating = "Good afternoon ";
var alertTime=""
}
else if (date >= "15:00:00" && date <="22:00:00"){
greating = "Good evening ";
var alertTime=""
}
else {
greating = " You should have some sleep !";
var alertTime = greating ;
};
//5//end
//
if (question[0] === "what"){
switch ( question[1]){
case "time":
switch (question[2]){
case "is":
switch (question[3]){
case "it":
write("The time is :"+date+alertTime);
break;
default:
};
break;
default:
} ;
break;
case "is":
switch (question[2]){
case "your" :
switch (question[3]){
case "name":
write("Alex !");
break;
case "father":
write("Medardo Erabti , he made me !");
break;
default:
};
break;
case "my":
switch (question[3]){
case "name":
write("Alex !");
break;
default:
};
break;
default:
};
break;
default: write("unknown");
};}
else if (question[0] === "my"){
switch (question[1]){
case "name":
switch(question[2]){
case "is":
userName = capitalize(question[3]);;
alert("Your name is saved, "+userName);
break;
default:
};
break;
default:
};
}
else if (question[0] === "should" || "could" || "may" || "can" ) {
switch (question[1]) {
case "i" :
switch(question[2]){
case "sleep":
write("Sure ! you can sleep if you want to !!");
break;
default:
}
break;
default:
};
}
if (question[0] === "who"){
switch (question[1]){
case "are":
write ("I'm Alex !");
break;
case "am":
write ("My leader !");
default:
}
};
return userName,greating ;
};
function deleteVal () {
var x = document.getElementById("lable").innerHTML = "" ;
return x ;
};
我尝试过的
试图禁用函数'randomArray（z）'中的'z'参数并将其替换为数组“ firstHello”的名称，其类型为“ undefined”在paragraf中，其ID为“ lable”。
最佳答案
在dosome函数中，创建一个名为userName的局部变量，与全局变量相同。局部变量将隐藏函数内部代码的全局变量，因此在调用函数后，全局变量仍将是未定义的。
关于randomArray函数中的代码的注释：
您正在使用Math.floor而不是Math.random。
创建整数随机数时请勿使用Math.round，这将使第一个和最后一个数字出现的频率是其他数字的一半。请改用Math.floor。
您的循环在数组的最后一项之外增加了两项。
您完全不需要循环即可获得具有特定索引的项目。
这是只显示修改后的randomArray函数的代码以及调用它的代码：
var greating = 'Hello', userName = 'sir';
var firstHello = [
[ greating + " " + userName + ", How can I help you ?" ],
[ "Hi " + userName + " how can i help ?" ],
[ greating + ", how can i help ?" ]
];
function randomArray(z) {
var index = Math.floor(Math.random() * z.length);
return z[index];
}
console.log(randomArray(firstHello));