String problems with Javascript double quotes inside single

This is my code:

<script>
    function popupTest(title) {
        alert(title);
        return false;
    }
</script>

<a href="" onclick="return popupTest('This is &#039;some&#039; &quot;test&quot; string')"><span>Recommend</span></a>

Using Firefox 4 I get the error:

Error: missing ) after argument list
Source Code:
return popupTest('This is 'some' "test" string')

It's like it's decoding the HTML entities but I don't know why.

Have also tried...

<a href="" onclick="return popupTest('This is \'some\' \"test\" string')"><span>Recommend</span></a>

Which gives error:

Error: unterminated string literal
Source Code:
return popupTest('This is \'some\' \