John B. Anderson, standing a weak third in polls in his home state of Illinois, wooed Jewish voters here today with an emotional attack on what he called "a dangerous resurgence of anti-Semitism."

Anderson appeared at a Northwestern University gathering organized by Jewish leaders in opposition to a Nazi rally scheduled for later in the afternoon. Eleven brown-shirted Nazi demonstrators were forced to desert that rally after a five-minute hail of rocks, eggs and tomatoes from counter-demonstrators. No injuries were reported but several arrests were made.

The confrontation came after 2,000 people from the Northwestern rally marched across town to the Nazi rally, planned as an hour of speeches promoting white supremacy.

At the earlier rally, Anderson, addressing a crowd of more than 5,000 on the Northwestern campus, said Jews and non-Jews alike must let it be known that "we will not tolerate this blot of anti-Semitism to spread in our land."

Citing the recent bombing of a Jewish synagogue in Paris and an upsurge in pro-Nazi and Ku Klux Klan activity in the United States, Anderson said that a growing tide of anti-Semitism is "a fact, a fact that has to be reckoned with in American life."

"An attack on Jews is by implication an attack on everyone," he said, "if we don't draw the line here and now, then how can we draw it anywhere."

The appearance was a politically opportune one for Anderson, who is currently drawing the support of about 20 percent of the nation's Jewish voters, according to recent Washington Post polls. This is a larger portion of the vote than he gets from any other ethnic group, and is damaging President Carter's chances in several large industrial states.

Leaders of the rally said they had also invited Carter and GOP candidate Ronald Reagan to attend, but both refused because of scheduling conflicts.

With only two weeks to go before the election, Anderson has the support of only 14.4 percent of Illinois voters, according to a poll published in the Chicago Sun-Times today. The poll showed Carter leading in the state with 43.9 percent. Reagan had 41.7 percent.

Meanwhile, the first network television advertisements Anderson's financially pressed campaign has been able to afford began to appear.

The five-minute ads focus on Anderson's background and his differences with Reagan and Carter on income tax cuts, increased defense spending and the arms race. The ads portray Reagan and Carter as having identical positions on these three issues.

They close with Anderson sitting behind a desk in his shirt-sleeves and looking into the camera as he says: "How would you feel if your vote on November 4 made possible not a lesser of evils, but a greater good, a new vision for our country. You can make it happen."