What does href expression do?

Question

I have seen the following href used in webpages from time to time. However, I don't understand what this is trying to do or the technique. Can someone elaborate please?

<a href="javascript:;"></a>

Answer 1

An <a> element is invalid HTML unless it has either an href or name attribute.

If you want it to render correctly as a link (ie underlined, hand pointer, etc), then it will only do so if it has a href attribute.

Code like this is therefore sometimes used as a way of making a link, but without having to provide an actual URL in the href attribute. The developer obviously wanted the link itself not to do anything, and this was the easiest way he knew.

He probably has some javascript event code elsewhere which is triggered when the link is clicked, and that will be what he wants to actually happen, but he wants it to look like a normal <a> tag link.

Some developers use href='#' for the same purpose, but this causes the browser to jump to the top of the page, which may not be wanted. And he couldn't simply leave the href blank, because href='' is a link back to the current page (ie it causes a page refresh).

There are ways around these things. Using an empty bit of Javascript code in the href is one of them, and although it isn't the best solution, it does work.

Answer 2

basically instead of using the link to move pages (or anchors), using this method launches a javascript function(s)

<script>
function doSomething() {
  alert("hello")
}
</script>
<a href="javascript:doSomething();">click me</a>

clicking the link will fire the alert.

Answer 3

There are several mechanisms to avoid a link to reach its destination. The one from the question is not much intuitive.

A cleaner option is to use href="#no" where #no is a non-defined anchor in the document.

You can use a more semantic name such as #disable, or #action to increase readability.

Benefits of the approach:

• Avoids the "moving to the top" effect of the empty href="#"
• Avoids the use of javascript

Drawbacks:

• You must be sure the anchor name is not used in the document.
• The URL changes to include the (non-existing) anchor as fragment and a new browser history entry is created. This means that clicking the "back" button after clicking the link won't behave as expected.

Since the <a> element is not acting as a link, the best option in these cases is not using an <a> element but a <div> and provide the desired link-like style.

Answer 4

It's used to write js codes inside of href instead of event listeners like onclick and avoiding # links in href to make a tags valid for HTML.

Interesting fact

I had a research on how to use javascript: inside of href attribute and got the result that I can write multiple lines in it!

<a href="
     javascript:
        a = 4;
        console.log(a++); 
        a += 2; 
        console.log(a++); 
        if(a < 6){ 
            console.log('a is lower than 6');
        } 
        else 
            console.log('a is greater than 6');
        function log(s){
            console.log(s);
        }
        log('function implementation working too');

">Click here</a>

• Tested in chrome Version 68.0.3440.106 (Official Build) (64-bit)

• Tested in Firefox Quantum 61.0.1 (64-bit)

Answer 5

<a href="javascript:alert('Hello');"></a>

is just shorthand for:

<a href="" onclick="alert('Hello'); return false;"></a>

Answer 6

It is a way of making a link do absolutely nothing when clicked (unless Javascript events are bound to it).

It is a way of running Javascript instead of following a link:

<a href="Javascript: doStuff();">link</a>

When there isn't actually javascript to run (like your example) it does nothing.

Answer 7

Refer to this:

<a href="Http://WWW.stackoverflow.com">Link to the website opened in different tab</a>
<a href="#MyDive">Link to the div in the page(look at the chaneged url)</a>
<a href="javascript:;">Nothing happens if there is no javaScript to render</a>

Answer 8

<a href="javascript:void(0);"></a>

javascript: tells the browser to execute the JavaScript code, and void(0) means, do nothing - don't reload, don't navigate, do not run any code.

Answer 9

Old thread but thought I'd just add that the reason developers use this construct is not to create a dead link, but because javascript URLs for some reason do not pass references to the active html element correctly.

e.g. handler_function(this.id) works as onClick but not as a javascript URL.

Thus it's a choice between writing pedantically standards-compliant code that involves you in having to manually adjust the call for each hyperlink, or slightly non-standard code which can be written once and used everywhere.

Answer 10

Since it is a styling issue, instead of polluting the HTML with non valid syntax, you could/should use a W3 valid workaround:

1. Format the HTML properly, without href, following the W3 accessibility guide lines for buttons.
2. Use CSS to fix the initial goal of applying a clickable UX effect on a control.

Here's a live example for you to try the UX.

HTML

    <a role="button" aria-pressed="false">Underlined + Pointer</a>
    <a role="button" aria-pressed="false" class="btn">Pointer</a>

CSS

    a[role="button"]:not([href]):not(.btn) { text-decoration: underline; }
    a[role="button"]:not([href]) { cursor: pointer; }

Answer 11

I was searching for a solution that does not refresh pages but opens menu items on Ipads and phones. I tried it on also mobile, It works well

<a href="#" onclick="return false;">Dr</a>

Answer 12

    1. Use that java script to Clear an HTML row Or Delete a row using the id set to a span and use JQuery to set a function to that span's click event.
    2. Dynamically set the div html to a string variable and replace {id} with a 1 or 2 etc. cell of a larger div table and rows

<div class="table-cell">
    <span id="clearRow{id}">
        <a href="javascript:" style-"color:#c32029; align:right; font-size:8pt;">Clear</a>
    </span>
</div>

<div class="table-cell">
   <span id="deleteRow{id}">
       <a href="javascript:" style-"color:#c32029; align:right; font-size:8pt;">Delete</a>
   </span>
</div>

//JQuery - Clear row
$("#clearRow" + idNum).click(function(){
    $("someIDOrWildcardSelector" + idNum).val("");
    $("someIDOrWildcardSelector" + idNum).val("");
    $("someIDOrWildcardSelector" + idNum).val("");
});

//JQuery to remove / delete an html row
$("#deleteRow" + idNum).click(function(){
    //depending upon levels of parent / child use 1 to many .parent().parent().parent()
    $(this).parent().remove();
});