I am using a js calendar script that populates a text field with a date. When clicking in the field the calendar shows then i choose a date, calendar closes, the date is now in the field. great it works fine.

example- *note, array use[]*

<input type="text" id="example[]" name="example[]" value="" onfocus="if(self.gfPop)gfPop.fPopCalendar(this);return false;">

I want to make this call from a button. when adding the code to a href, the popup shows but nothing happens when selecting a date. I have tried the following scripts will failure.

*html a href and img tag left out*

onclick="if(self.gfPop)gfPop.fPopCalendar(document.this_form.elements['example[]']);return false;"

onclick="if(self.gfPop)gfPop.fPopCalendar(document.this_form.example[]);return false;"

onclick="if(self.gfPop)gfPop.fPopCalendar(this);return false;"

Try this:

onclick="if(self.gfPop)gfPop.fPopCalendar(document.this_form['example[]']);return false;"

Your second example was almost right. In JS you can access properties via the "dot" notation, or array notation. But since you have special characters (the []'s) in your field name, you are forced to use the array notation. That is, these two are the same:

myvar = someobj.prop;
// and
myvar = someobj['prop'];

But in the case where 'prop' has special characters, there is only one way:

myvar = someobj.prop!;// wont work
myvar = someobj['prop!']; // will work

Your first try could be correct if you knew the field index. form.elements[] is a numeric array with indexing starting at 0 which equals the first element in the form.