value 2 « variable « Javascript Data Type Q&A

1. Setting a values based on a variable control name.    sitepoint.com

2. check for variable/ value existence    sitepoint.com

Is there a way of checking for variables existence without error. I'm trying to check if a form element exists - if (window.opener.document.forms[0].absent_table.value) { // do something } whenever this form element isn't present, I'm informed with an ugly error message. This is perfectly possible in PHP with the isset(), empty() functions which has no relevance to my problem at ...