javascript copying element value, where element name has a period

If an html element id has no period in it, then copying between elements is of course trivial, e.g.:

 var theForm = document.paymentForm;
 theForm.BillStreet1.value = th开发者_如何学运维eForm.ShipStreet1.value;

I've got a case where I need to have period in my ids, namely id="bill.street1" and id="ship.street1", and the following doesn't work :-(

 theForm.bill.street1.value = theForm.ship.street1.value;

Can you please let me know how to handle the period? Does jquery make this simpler?

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jQuery makes everything simplier by using css selectors to access elements. However, if you don't want to use jQuery, you can access the element this way, I believe.

theForm['bill.street1'].value = theForm['ship.street1'].value;

I haven't tested this, but it should work because periods are an alternate method to access an array, iirc.

Be sure to use theForm['bill.street1'].value = theForm['ship.street1'].value; and not theForm.['bill.street1'].value = theForm.['ship.street1'].value;. The extra periods make the format invalid, in the same way using array.[2] instead of array[2] would invalidate it.

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theForm['bill.street1'].value
theForm['ship.street1'].value