I have a very old Rails 3 project I'm maintaining, to which I need to add new functionality. Primarily responsiveness with Bootstrap 4.

This is what I actually want to create:

CodePudding user response：

You can add ' when you build the li.

"<li class='"   li_class   "'>"   list_details_html   "</li>"

as you can see in the example, I've added a console log, it returns <li class=list-group-item card-list-best>test</li> so if there no " or ' after class= then it will take the value after = and until the first space, so it would return <li class="list-group-item">test</li>

Working example

var li_class = "";
var list_details_html = "test";
li_class = "list-group-item";
li_class  = " card-list-best";
var list_html = $(
  "<li class='"   li_class   "'>"   list_details_html   "</li>"
);

console.log("<li class="   li_class   ">"   list_details_html   "</li>")

$('ul').append(list_html)

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<ul></ul>