好吧，这就是我被卡住的地方。对于我在这个基本程序中的最后条件。如果用户得分为0，我想添加图像。如何添加图像。我已经在.js和.html文件所在的文件夹中放了一张图片。但是有什么代码可以插入我存档的图像。我在.js写了笔记，所以你们可以理解。
//user score is 0
var userscore = 0;
//this is question 1
var question1 = prompt('What is 2 + 2?');
if (question1 === "4")
{ userscore = userscore +1;
alert("Congrats thats right!");}
else { alert("that is incorrect try again")}
//this is question 2
var question2 = prompt('What is 2 * 2?');
if(question2==="4")
{ userscore = userscore +1;
alert("Congrats thats right!")}
else {alert("that is incorrect try again")}
//this is question 3
var question3 = prompt("what is 20 + 5?");
if(question3 === "25")
{userscore = userscore +1;
alert("Congrats thats right!")}
else{alert("that is incorrect try again")}
//Scoring Guide
if (userscore === 2)
{document.write("Congrats You have passed the test with a score of 2/3")}
if(userscore === 3)
{document.write("Congrats You have passed the test with a score of 3/3")}
if(userscore === 1)
{document.write("You Failed with a score of 1/3, you are not very Bright")}
if(userscore === 0)
{document.write("You have a score of 0, your a complete idiot.")}
//I want to add an image instead of the document.write command for the last line if they recieve a score o 0而不是document.write，只需创建一个img元素，设置源，然后将其附加到目标（我编写目标代码，如果你只想附加到body），如下：
if(userscore === 0)
{
var img = document.createElement("img");
img.src = "/score0.png";
var src = document.getElementById("target"); //if you want a specific source
//var src = document.body; if you just want to append to body
src.appendChild(img);
}
您将要将图像添加到项目的目录中，如下所示：
在这种情况下，你只需将/image.png作为路径。
这不是好方法。但在你的情况下，这是有效的。只需用img标签替换字符串即可
<img src='image_name.extension' />
请记住使用单引号。
//user score is 0
var userscore = 0;
//this is question 1
var question1 = prompt('What is 2 + 2?');
if (question1 === "4")
{ userscore = userscore +1;
alert("Congrats thats right!");}
else { alert("that is incorrect try again")}
//this is question 2
var question2 = prompt('What is 2 * 2?');
if(question2==="4")
{ userscore = userscore +1;
alert("Congrats thats right!")}
else {alert("that is incorrect try again")}
//this is question 3
var question3 = prompt("what is 20 + 5?");
if(question3 === "25")
{userscore = userscore +1;
alert("Congrats thats right!")}
else{alert("that is incorrect try again")}
//Scoring Guide
if (userscore === 2)
{document.write("Congrats You have passed the test with a score of 2/3")}
if(userscore === 3)
{document.write("Congrats You have passed the test with a score of 3/3")}
if(userscore === 1)
{document.write("You Failed with a score of 1/3, you are not very Bright")}
if(userscore === 0)
{document.write("<img src='test.JPG' />")}
//I want to add an image instead of the document.write command for the last line if they recieve a score o 0首先，你应该避免一次又一次地复制粘贴相同的代码。相反，您可以重用相同的代码，如下所示
<html>
<head>
<script>
//user score is 0
var userscore = 0;
// common function for question
var questionFunc = function(question, answer){
var user_answer = prompt(question);
if (user_answer === answer)
{
userscore = userscore +1;
alert("Congrats thats right!");
}else {
alert("that is incorrect try again");
}
}
//this is question 1
questionFunc('What is 2 + 2?','4');
//this is question 2
questionFunc('What is 2 * 2?','4');
//this is question 3
questionFunc('what is 20 + 5?','25');
//Scoring Guide
if (userscore === 2)
{document.write("Congrats You have passed the test with a score of 2/3")}
if(userscore === 3)
{document.write("Congrats You have passed the test with a score of 3/3")}
if(userscore === 1)
{document.write("You Failed with a score of 1/3, you are not very Bright")}
if(userscore === 0)
{document.write("<img src='test.JPG' />")}
//I want to add an image instead of the document.write command for the last line if they recieve a score o 0
</script>
</head>
<body>
</body>
</html>
尝试以相同的方式实现评分指南（使用该功能）。然后添加更多问题和答案将很容易。也不是使用普通的javascript进行这种工作，更好地使用像JQuery这样的javascript框架。它会更清洁，更容易。