I stumbled upon this when I had to avoid a page refresh that was triggered due to selection of the property named "Refresh fields on keyword change" for a combobox field type in the lotus notes form.
It was like there were no ways to impose a partial refresh of web page segments like the ones available with XPages. Eventually search for a desparate hack went in vain but I was able to discover the existence of this particular hack.
Hope this helps some one though I did not have any use for the same. Following is what I am speaking about.
1. Create a form. Include a dropdown "combo" field in it. Give it some options and select the property "Refresh fields on keyword change".
2. The property selection I am speaking about is illustrated as follows
3. Put a date time field near by the combo box and ensure that it displays time upto seconds at any point of its display
_doClick('$Refresh', this, '_self', '#_RefreshKW',"myDropDown")
9. Now save and preview your webpage again and try changing the values in the dropdown again. You will be able to recognize that the page behaves in a simialr way and it is no different from the property selection on the dropdown field.
10. Interesting right.
Now my worry is I guess, I will be able to perform a few hacks with this. So more to think about when developing webpages in future :(
Hope this helps :)