Simple PHP/JS Question-Answer

using just basic JS no Jquery... We have a form that posts to another website outside of out control (to capture email address). when the user submits the form the data is checked with a js function to validate the data... ex: validate(form){ var from = [login to view URL]; if ([login to view URL] === 0) { alert("Please Enter your Email Address."); return false; } The form posts to an external site (so we have no control over it) something like [login to view URL] The problem is, the form is optional, and if it is filled out we want it to post the data as entered to the external site as normal. However, if there is no data (someone just clicks the submit button) we want the site to redirect the user to a different page. Tried, if (from.length===1){ [login to view URL] } (for testing to see if a [login to view URL] would work) That is not working. Probably simple for someone knowledgeable. Recap. Form submits to external site, if user enters nothing then redirect to a different site/url.