Reading dynamically named form element’s value

I need to read data from a dynamically named form element. Sometimes the element will start with the word “New” and sometimes it will be “Upd.”

I’m using the following function to test which one exists:

function isObject(element) {
return (typeof element == ‘object’);
}

Why will the following not work? I get an ‘Expected Identifier’ error.

if (isObject( document.frmData.[“New-” + arr1[h] + “-” + arr2[h] ] ) == true) {
alert( document.frmData.[“New-” + arr1[h] + “-” + arr2[h] ].value )
}

The arrays hold the rest of the dynamic name. I’ve checked the value of

[“New-” + arr1[h] + “-” + arr2[h] ]

with an alert box–it is the correct element name. Why won’t this work?

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