Please before posting or commenting ... read and understand that this is inside an application that generates the web page and I cannot create a function I can only edit with will happen inside the onclick

Is it possible to use a if function inside an onclick.

The reason why I have to do this is because this onclick is used inside an application that I do not control the code, the only thing I can control is what happens inside the onclick

For example:

onclick=document.getElementById('REF_DOC_1_NUMBER').value = '';

I can write the:

document.getElementById('REF_DOC_1_NUMBER').value = '';

I cannot declare any function in the webpage... cause it's an application that compiles the pages... I can only write what is written in the tag onclick...

But not a function. The page is generated by the application itself so I do not control the header.

What I need, a IF that checks an other ID and to change the value ONLY if the value of the other ID (REF_DOC_1_CHOICE) is NA (not applicable)

Any thoughts?