Question

I have this javascript in a classic asp page…

I need to find out if x.name is undefined or has a value:

x=document.getElementsByTagName("meta")[i];
if (String(x.name) != "undefined" && String(x.name) != ""){
document.write(""+x.name +": "+x.content+"<br><br>");
}

I am not sure why it is throwing an error:

document.write(""+x.name +": "+x.content+"<br><br>");

if x.name or x.content is false?

Thanks

Answer 1

To check for undefined:

if (typeof x !== 'undefined') {
  if (x.name) {
    document.write(x.name + ': ' + x.content + '<br><br>');
  }
}

Now, I don’t know what you’re trying to do with that document.write() call, so that might cause problems too, but the above will make sure you only do it when “x” exists and has a non-empty “name” attribute.