detecting 'undefined'

[shmmeee]

OK you guys were so helpful with my last post I thought I'd give you my next problem. My code is as follows:

function get_defn(term_string)
{
	defn_string = eval(term_string.replace(/ /g,"_").toUpperCase());
	defn_array = defn_string.split("=");
	return defn_array[0]
};
function write_link()
{
	linkspot.innerHTML = '<a href=&quot;' + defn_array[1] + '&quot;>More Information</a>'
}

Defn_string is set out like this: description=URL
So defn_array[1] holds the URL, however for some descriptions there is no URL so defn_string is just: description
and defn_array[1] = 'undefined'
can I detect the absence <sp?> of a URL and act accordingly e.g:

function write_link()
{
if(defn_array[1]!='undefined')
	linkspot.innerHTML = '<a href=&quot;' + defn_array[1] + '&quot;>More Information</a>'
else
        linkspot.innerHTML = 'No link available';
}


Iain X-)

 

[jaredn]

the following will return true if defn_array[1] is undefined:

if(typeof(defn_array[1])=='undefined') jared@eae.net -

http://webfx.eae.net

 

[shmmeee]

Thanks