When designing forms on the web, a little thing can help out your users. In the Notes client, it's called field level help text and probably isn't used very much. To duplicate the same thing on the web, you can set the window status bar when focus is entered in the field. However, a better solution is to combine that technique with pop-up help that works in IE and Netscape 6+. The popup-help is created by using the "title" attribute on an input tag. For example, mouse over this field:

If you have a browser that supports it, then mousing over should pop up some help text: "This is pop-up help for this field".

So, a good habit to get into would be to go to the HTML attributes of your input fields and add a formula similar to this:
"onblur=\"window.status=window.defaultStatus; return true;\" onfocus=\"window.status=\'Please fill in your name\'; return true;\" title=\"Please fill in your name\""

This code says that when you tab into the field, change the status bar text. This will work on browsers like Netscape 4 that support JavaScript but don't recognize the title attribute. For browsers that do recognize the title attribute, mousing over the field will pop up field help in addition to changing the status bar when a user tabs into the field. When a user tabs away from the field, the status bar is reset to the default value.