javascript - How to disable HTML links

Question

I have a link button inside a <td> which I have to disable. This works on IE but not working in Firefox and Chrome. Structure is - Link inside a <td>. I cannot add any container in the <td> (like div/span)

I tried all the following but not working on Firefox (using 1.4.2 js):

$(td).children().each(function () {
        $(this).attr('disabled', 'disabled');
  });


  $(td).children().attr('disabled', 'disabled');

  $(td).children().attr('disabled', true);

  $(td).children().attr('disabled', 'true');

Note - I cannot de-register the click function for the anchor tag as it is registered dynamically. AND I HAVE TO SHOW THE LINK IN DISABLED MODE.

Answer 1

You can't disable a link (in a portable way). You can use one of these techniques (each one with its own benefits and disadvantages).

CSS way

This should be the right way (but see later) to do it when most of browsers will support it:

a.disabled {
    pointer-events: none;
}

It's what, for example, Bootstrap 3.x does. Currently (2016) it's well supported only by Chrome, FireFox and Opera (19+). Internet Explorer started to support this from version 11 but not for links however it's available in an outer element like:

span.disable-links {
    pointer-events: none;
}

With:

<span class="disable-links"><a href="#">...</a></span>

Workaround

We, probably, need to define a CSS class for pointer-events: none but what if we reuse the disabled attribute instead of a CSS class? Strictly speaking disabled is not supported for <a> but browsers won't complain for unknown attributes. Using the disabled attribute IE will ignore pointer-events but it will honor IE specific disabled attribute; other CSS compliant browsers will ignore unknown disabled attribute and honor pointer-events. Easier to write than to explain:

a[disabled] {
    pointer-events: none;
}

Another option for IE 11 is to set display of link elements to block or inline-block:

<a style="pointer-events: none; display: inline-block;" href="#">...</a>

Note that this may be a portable solution if you need to support IE (and you can change your HTML) but...

All this said please note that pointer-events disables only...pointer events. Links will still be navigable through keyboard then you also need to apply one of the other techniques described here.

Focus

In conjunction with above described CSS technique you may use tabindex in a non-standard way to prevent an element to be focused:

<a href="#" disabled tabindex="-1">...</a>

I never checked its compatibility with many browsers then you may want to test it by yourself before using this. It has the advantage to work without JavaScript. Unfortunately (but obviously) tabindex cannot be changed from CSS.

Intercept clicks

Use a href to a JavaScript function, check for the condition (or the disabled attribute itself) and do nothing in case.

$("td > a").on("click", function(event){
    if ($(this).is("[disabled]")) {
        event.preventDefault();
    }
});

To disable links do this:

$("td > a").attr("disabled", "disabled");

To re-enable them:

$("td > a").removeAttr("disabled");

If you want instead of .is("[disabled]") you may use .attr("disabled") != undefined (jQuery 1.6+ will always return undefined when the attribute is not set) but is() is much more clear (thanks to Dave Stewart for this tip). Please note here I'm using the disabled attribute in a non-standard way, if you care about this then replace attribute with a class and replace .is("[disabled]") with .hasClass("disabled") (adding and removing with addClass() and removeClass()).

Zoltán Tamási noted in a comment that "in some cases the click event is already bound to some "real" function (for example using knockoutjs) In that case the event handler ordering can cause some troubles. Hence I implemented disabled links by binding a return false handler to the link's touchstart, mousedown and keydown events. It has some drawbacks (it will prevent touch scrolling started on the link)" but handling keyboard events also has the benefit to prevent keyboard navigation.

Note that if href isn't cleared it's possible for the user to manually visit that page.

Clear the link

Clear the href attribute. With this code you do not add an event handler but you change the link itself. Use this code to disable links:

$("td > a").each(function() {
    this.data("href", this.attr("href"))
        .attr("href", "javascript:void(0)")
        .attr("disabled", "disabled");
});

And this one to re-enable them:

$("td > a").each(function() {
    this.attr("href", this.data("href")).removeAttr("disabled");
});

Personally I do not like this solution very much (if you do not have to do more with disabled links) but it may be more compatible because of various way to follow a link.

Fake click handler

Add/remove an onclick function where you return false, link won't be followed. To disable links:

$("td > a").attr("disabled", "disabled").on("click", function() {
    return false; 
});

To re-enable them:

$("td > a").removeAttr("disabled").off("click");

I do not think there is a reason to prefer this solution instead of the first one.

Styling

Styling is even more simple, whatever solution you're using to disable the link we did add a disabled attribute so you can use following CSS rule:

a[disabled] {
    color: gray;
}

If you're using a class instead of attribute:

a.disabled {
    color: gray;
}

If you're using an UI framework you may see that disabled links aren't styled properly. Bootstrap 3.x, for example, handles this scenario and button is correctly styled both with disabled attribute and with .disabled class. If, instead, you're clearing the link (or using one of the others JavaScript techniques) you must also handle styling because an <a> without href is still painted as enabled.

Accessible Rich Internet Applications (ARIA)

Do not forget to also include an attribute aria-disabled="true" together with disabled attribute/class.