javascript - 如何打印这条随机线？

Question

这是我的代码

var e=document.getElementById('button');
e.addEventListener('click',function yo(e)
{e.preventDefault();
var a=[
        {'quote':"Result: something good is going to happen with you",},
        {'quote':"Result: your future is very bright i think you are going to meet someone special in your life",},
        {'quote':"Result: just be careful things are not looking good",},
        {'quote':"Result: just be patient in your life if you want everything fine",},
        {'quote':"Result: ohh its difficult please retry ",},
        {'quote':"Result: daymn a good news is coming ",},
        {'quote':"Result: be ready for the upcoming storm my friend",},
        {'quote':"Result:  i dont want to tell you ryt now",},
    
];
var count=0;
var b=document.getElementById('user');
var c=document.createElement('p');
var d=document.getElementById('ha');
var f="";
i=Math.floor(Math.random()*8);//Here alone Math.random*8 gives the number between 0 to 7 and always in float
    //so to make it as whole number we put it inside Math floor
    c=b.value;

var l=a[i].quote;
f="<p>Result: "+ c + +l+  "</p>"
d.insertAdjacentHTML('beforeend',f);    
})

我的问题是，当我输入用户名时，它确实出现在一个段落中，但它没有显示引号，而是显示了 NaN。

Answer 1

正是这里的这一行导致了问题:

f="<p>Result: "+ c + +l+  "</p>"

如果我们尝试按照 JavaScript 的理解来分解它，我们会得到

• f = (作业)
• "<p>Result: " (字符串)
• + (串联)
• c (c中的值)
• + (串联)
• +l (对 l 中的值进行一元运算)
• + (串联)
• "</p>" (字符串)

所以你正在连接一堆字符串，但是额外的+正在获取一个字符串并尝试将其转换为数字。正如您可以想象的那样，报价不是数字，因此 NaN