Besides the US government putting Japanese Americans into internment camps for no reason, what were other examples of prejudice against Asians during WWII?
The above post notes a Bugs Bunny cartoon. It should be noted also that in one cartoon, a character is portrayed as Japanese with large thick glasses. This was an unmistakable caricature of the Japanese Prime Minister Hediki Tojo. Japanese Americans were often refused service at restaurants, hotels, etc. One barber shop hung a sign outside its storefront window which read, "Free shaves for Japs; not responsible for accidents."
One must bear in mind that at the time, many Americans did not distinguish between patriotism and racial intolerance. Interestingly, Americans of German or Italian descent were not forced into camps; nor did they suffer the discrimination and suspicion that was aimed at Japanese Americans. My Grandson is a Japanese American. I am not sure how I could abide that type of discrimination if it were aimed at him.
Of course, the internment was the biggest example. The other clear examples I can think of come from popular culture.
There was, for example, a song called "You're a Sap, Mr. Jap." I don't know if you would say that calling people "Japs" back then was a form of prejudice, but I think it was. There was also a Popeye the Sailor cartoon of the same name.
In that cartoon and in other cartoons of the time (there's a Bugs Bunny cartoon where he gets stuck on an island in the South Pacific and has to fight a lot of Japanese -- it's called "Bugs Bunny Nips the Nips"), Japanese are portrayed in very stereotypical ways. They are shown as excessively slanty-eyed and bucktoothed. They are all wearing glasses and they talk really funny.
That sort of popular culture thing was aimed at actual Japanese (as opposed to Japanese Americans) but they played on racial stereotypes. I would see those as examples of prejudice against Asians.
You can also find propaganda posters that were pretty anti-Japanese. For example, the one in this link refers to the need to "wipe out" "every murdering Jap."