Form Validation

I'm using the following to validate that an entry has been made before sending form values using mailto. However, this sends the email whether the data is valid or not. This function is called form the onClick event of the Submit button - I must need to replace the 1st 'return' with another command?
Any thoughts?
thanks

function validateIt()
{
var txtText
txtText = document.request.company.value;
if(txtText.length < 1) /
{
alert("Must enter a value");
txtText.focus;
return;
}
/* input ok */
return;
}

Isn't it a javascript (or ECMASCRIPT)? If this is the case, post it to the appropriate forum, and notice that data validation is better done on server side!