Simulating A Multi Array - More Than One Textarea

I have a section of javascript that declares a global variable for a few functions, like this incomplete code

Code:

The above, in its full version, changes the text in a textarea. In my php code, if I include the above code above the textarea, it all works as expected.

The problem is that I may have more than one textarea - the number cannot be known beforehand. If I include the above before each textarea, the pointer gets confused as to which string belongs to which textarea since the global variables get redefined many times. In php, this would be a simple problem to solve with a mutildimensional array but, from what I understand, javascript doesn't have such arrays.

Someone can provide a solution that will allow me to use the same block of code over and over in the same file.