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opener.document.forms.plugin-media4pic.value = "avatar.jpg";
All I was trying to do was update a field on the parent form that called a popup with an image that had been uploaded by the user. Sounds pretty straightforward, and I had used that type of code in the past when building the WP Auctions plugin. So I expected it to work right off the bat.
Instead, I kept getting an error saying “invalid assignment left-hand side”. I rechecked my code. I walked through the page DOM to ensure I wasn’t specifying something that didn’t exist. I rechecked my code. I went for a walk. I rechecked my code. I made some tea. I rechecked my code. I scratched my head for a bit. I rechecked my code. Nothing. I still kept getting the pesky error.
Eventually, out od desperation, I started trying different things, and found out what the problem was!
Hope you guys don’t run into something else inexplicable today.