JavaScript splice() 方法第三个参数无法识别

Question

javascript

Answer 1

document.write("<span style='color:yellow'>a.splice(3,1,\"a\"):&nbsp"+a.splice(3,1,"a")+"</span></br>");

Answer 2

<script>
document.write("<div id='show'>");
 
        var a=[23,566,3,78,6,633,42,5,7867,34,774,3];
        document.write("a:&nbsp"+a+"</br>");
         
        //splice第一个参数表示删除位置，第二个表示删除个数
        document.write("<span style='color:green'>a.splice(10):&nbsp"+a.splice(10)+"</span></br>");
        document.write("a:&nbsp"+a+"</br>");
        document.write("<span style='color:red'>a.splice(1,3):&nbsp"+a.splice(1,3)+"</span></br>");
        document.write("a:&nbsp"+a+"</br>");
        document.write("<span style='color:red'>a.splice(3,1):&nbsp"+a.splice(3,1)+"</span></br>");
        document.write("a:&nbsp"+a+"</br>");
        a.splice(1,1,"b");//这个有问题
        document.write("<span style='color:yellow'>a.splice(3,1,\"a\"):&nbsp"+a.splice(3,1,"a")+"</span></br>");
        document.write("a:&nbsp"+a+"</br>");
 
           document.write("</div>");
  console.log(1)
</script>

Answer 3

换成单引号就可以了
document.write("<span style='color:yellow'>a.splice(3,1,'a'):&nbsp"+a.splice(3,1,'a')+"</span></br>");
但是看书上都是双引号，不知道是不是要设置什么