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JavaScript: changing the value of onclick with or without jQuery

Answer 1

A:

If want to change what happens "onClick" maybe you should bind an click handler instead, and "prevent default" from it?

$("#something").click(function(){
  //do your js here
  return false;
});

mkoryak 2009-05-05 19:55:38

The question is: how to I run that js code which I have in a string? I can't do eval(js), because js can contain a "return ...").

Alessandro Vernet 2009-05-05 20:09:15

Answer 2

A:

One gotcha with Jquery is that the click function do not acknowledge the hand coded onclick from the html.

So, you pretty much have to choose. Set up all your handlers in the init function or all of them in html.

The click event in JQuery is the click function $("myelt").click (function ....).

Tom Hubbard 2009-05-05 19:56:31

Tom, I can't use $("myelt").click() here because the code I want to run is in a string. (See my comments to other answers here as well.)

Alessandro Vernet 2009-05-05 20:10:39

Ah. I see how about: function js() { alert('B'); return false; }

Tom Hubbard 2009-05-05 20:23:29

Answer 3

+9 A:

You shouldn't be using onClick any more if you are using jQuery. jQuery provides its own methods of attaching and binding events. See .click()

$(document).ready(function(){
    var js = "alert('B:' + this.id); return false;";
    // create a function from the "js" string
    var newclick = new Function(js);

    // clears onclick then sets click using jQuery
    $("#anchor").attr('onclick', '').click(newclick);
});

That should cancel the onClick function - and keep your "javascript from a string" as well.

The best thing to do would be to remove the onclick="" from the <a> element in the HTML code and switch to using the Unobtrusive method of binding an event to click.

You also said:

Using onclick = function() { return eval(js); } doesn't work because you are not allowed to use return in code passed to eval().

No - it won't, but onclick = eval("(function(){"+js+"})"); will wrap the 'js' variable in a function enclosure. onclick = new Function(js); works as well and is a little cleaner to read. (note the capital F) -- see documentation on Function() constructors

gnarf 2009-05-05 20:07:24

Answer 4

A:

just use jQuery bind method !jquery-selector!.bind('event', !fn!);

See here for more about events in jQuery

Trickster 2009-05-05 20:12:45

Answer 5

A:

Came up with a quick and dirty fix to this. Just used <select onchange='this.options[this.selectedIndex].onclick();> <option onclick='alert("hello world")' ></option> </select>

Hope this helps

Afterburner 2009-11-02 13:14:00

Mmmh... sorry but I don't see how this is answer to the original question.

Alessandro Vernet 2009-11-02 22:18:41

Answer 6

A:

If you don't want to actually navigate to a new page you can also have your anchor somewhere on the page like this.

<a id="the_anchor" href="">

And then to assign your string of JavaScript to the the onclick of the anchor, put this somewhere else (i.e. the header, later in the body, whatever):

<script>
    var js = "alert('I am your string of JavaScript');"; // js is your string of script
    document.getElementById('the_anchor').href = 'javascript:' + js;
</script>

If you have all of this info on the server before sending out the page, then you could also simply place the JavaScript directly in the href attribute of the anchor like so:

<a href="javascript:alert('I am your script.'); alert('So am I.');">Click me</a>

ntownsend 2009-11-02 13:41:20

Answer 7

A:

Note that following gnarf's idea you can also do:

var js = "alert('B:' + this.id); return false;";
var newclick = eval("(function(){"+js+"});");
$("a").get(0).onclick = newclick;

That will set the onclick without triggering the event (had the same problem here and it took me some time to find out).

Eduardo 2009-11-04 21:03:09

Answer 8

A:

BTW, without JQuery this could also be done, but obviously it's pretty ugly as it only considers IE/non-IE:

if(isie)
   tmpobject.setAttribute('onclick',(new Function(tmp.nextSibling.getAttributeNode('onclick').value)));
else
   $(tmpobject).attr('onclick',tmp.nextSibling.attributes[0].value); //this even supposes index

Anyway, just so that people have an overall idea of what can be done, as I'm sure many have stumbled upon this annoyance.

Eduardo 2009-11-04 21:18:28

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JavaScript: changing the value of onclick with or without jQuery

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