Question

I’m searching for a solution that lets users click on links only if the radio buttons are checked. Otherwise it should a message should appear (popup).

Here is my code:

<div id="rightnav">
        <a href="katan_checklist_walkaroundcheck.html">Next</a></div>
</div>

<li class="radiobutton"><span class="name">Struct. Temp. Indic.> 38°C -not exceed 55°C</span>
            <input name="1" type="radio" value="other" /></li>
            <li class="radiobutton"><span class="name">Airplane Documents - check </span>
            <input name="2" type="radio" value="other" /></li>
            <li class="radiobutton"><span class="name">Flight Control Lock - removed</span>
            <input name="3" type="radio" value="other" /></li>
...

Answer 1

You can do something like this:

var anchor = document.getElementById('a_next');
anchor.onclick = function(event){
    var checked = false;
    for(var i = 1; i < 4; ++i){             
        if (document.getElementsByName(i)[0].checked) {
            checked = true;
        }                 
    }
    return checked;
}

Where ‘a_next’ is id of the anchor.

jsfiddle