call javascript function on hyperlink click
call javascript function on hyperlink click
Question
I am dynamically creating a hyperlink in the c# code behind file of ASP.NET. I need to call a JavaScript function on client click. how do i accomplish this?
Accepted Answer
Neater still, instead of the typical href="#" or href="javascript:void" or href="whatever", I think this makes much more sense:
var el = document.getElementById('foo');
el.onclick = showFoo;
function showFoo() {
alert('I am foo!');
return false;
}
<a href="no-javascript.html" title="Get some foo!" id="foo">Show me some foo</a>
If Javascript fails, there is some feedback. Furthermore, erratic behavior (page jumping in the case of href="#", visiting the same page in the case of href="") is eliminated.
Popular Answer
The simplest answer of all is...
<a href="javascript:alert('You clicked!')">My link</a>Or to answer the question of calling a javascript function:
<script type="text/javascript">
function myFunction(myMessage) {
alert(myMessage);
}
</script>
<a href="javascript:myFunction('You clicked!')">My link</a>Read more... Read less...
With the onclick parameter...
<a href='http://www.google.com' onclick='myJavaScriptFunction();'>mylink</a>
The JQuery answer. Since JavaScript was invented in order to develop JQuery, I am giving you an example in JQuery doing this:
<div class="menu">
<a href="http://example.org">Example</a>
<a href="http://foobar.com">Foobar.com</a>
</div>
<script>
jQuery( 'div.menu a' )
.click(function() {
do_the_click( this.href );
return false;
});
// play the funky music white boy
function do_the_click( url )
{
alert( url );
}
</script>
I prefer using the onclick method rather than the href for javascript hyperlinks. And always use alerts to determine what value do you have.
<a href='#' onclick='jsFunction();alert('it works!');'>Link</a>
It could be also used on input tags eg.
<input type='button' value='Submit' onclick='jsFunction();alert('it works!');'>
Ideally I would avoid generating links in you code behind altogether as your code will need recompiling every time you want to make a change to the 'markup' of each of those links. If you have to do it I would not embed your javascript 'calls' inside your HTML, it's a bad practice altogether, your markup should describe your document not what it does, thats the job of your javascript.
Use an approach where you have a specific id for each element (or class if its common functionality) and then use Progressive Enhancement to add the event handler(s), something like:
[c# example only probably not the way you're writing out your js]
Response.Write("<a href=\"/link/for/javascriptDisabled/Browsers.aspx\" id=\"uxAncMyLink\">My Link</a>");
[Javascript]
document.getElementById('uxAncMyLink').onclick = function(e){
// do some stuff here
return false;
}
That way your code won't break for users with JS disabled and it will have a clear seperation of concerns.
Hope that is of use.
I would generally recommend using element.attachEvent (IE) or element.addEventListener (other browsers) over setting the onclick event directly as the latter will replace any existing event handlers for that element.
attachEvent / addEventListening allow multiple event handlers to be created.