Javascript：条件函数onClick按钮

Question

I have to functions: openNav and closeNav and a button:

 <a href="#" data-toggle="sidebar-collapse-button">
                    <img class="sidebar-img" id = "collapse-img" src="${pageContext.request.contextPath}/imgs/main/sidebar/collapse.png"/>
                    <span class="sidebar-text">Collapse</span>
 </a>

A try to set a conditional onClick like this:

var collapsed = 0;

$('[data-toggle=sidebar-collapse-button]').click(function() {
    if (collapsed==0)  {
    closeNav();
    }
    else  {
        openNav();
    }    

});

So that when collapsed = 1 function openNav is called and vice versa:

function openNav() {
    ...

    collapsed=0;
}

function closeNav() {
    ...

    collapsed=1;
}

However it only works the first time to call closeNav and then the button doesn't react at all.

Answer 1

Here is a simple toggler in vanilla Javascript. I am not sure want you want to do or what frameworks you use but this is the basic idea

 <a href="#" onCLick="toggleSidebar()" data-toggle="sidebar-collapse-button">
  <span class="sidebar-text">Collapse</span>
 </a>

<div id="myDiv">
  Collapsed div
</div>

toggleSidebar = () => {
  let element = document.getElementById("myDiv")
  if(element.classList.contains("mystyle")){
    element.classList.remove("mystyle");
  } else  element.classList.add("mystyle");
}

Answer 2

As @connexo said, I would be inclined to use a toggle as well - if it is a show and hide you are trying to achieve.

If you want to use your logic, you can do something like this using a data attribute (or something similar):

Eg:

<a href="#" data-toggle="sidebar-collapse-button" data-state="0">
                    <img class="sidebar-img" id = "collapse-img" src="https://via.placeholder.com/150"/>
                    <span class="sidebar-text">Collapse</span>
 </a>

And for your script you can use:

var collapsed = 0;

$('[data-toggle=sidebar-collapse-button]').click(function() {
    var state = $(this).data('state');
    if (state == "0") {
        console.log("Closed");
      $(this).data('state','1')
    } else {
        console.log("Opened");
      $(this).data('state','0')
    }
console.log(state);
});

Further reading on data: .data()