Main intervention: A worksheet using pictures and texts to introduce the tobacco industry's marketing tactics to attract children and adolescents to smoke and their manipulation of tobacco control policy formation.

Booster intervention: 8 pictures from the TID worksheet in the main intervention and 6 true or false questions.

Main intervention: A worksheet using pictures and texts to introduce the beverage industry's marketing tactics to attract children and adolescents to drink SSBs and the health risks of SSBs.

Booster intervention: 8 pictures from the SSB worksheet in the main intervention and 6 true or false questions.

1. Tobacco industry conceals the harms of smoking products for commercial gain.
2. Tobacco industry deceives the public for commercial gain.
3. Tobacco industry uses many tactics to resist tobacco control regulations.

All the statements have 5 options from strongly disagree to strongly agree. The options were scored as 1-5, with higher scores indicating stronger TID beliefs.

1. ECs and HTPs are less harmful than cigarettes.
2. HTPs contain many carcinogens.

Both statements have 5 options from strongly disagree to strongly agree. The options were scored as 1-5 or 5-1, as appropriate, with higher scores indicating better knowledge.

1. Do you think trying a few puffs of ECs will harm your health?
2. Do you think trying a few puffs of HTPs will harm your health?

Both statements have 11 options from not harmful at all to very harmful. The options were scored as 0-10, with higher scores indicating stronger anti-tobacco attitudes.

1. Do you think it is acceptable for primary school students to try a few puffs of ECs?
2. Do you think it is acceptable for primary school students to try a few puffs of HTPs?

Both statements have 11 options from very unacceptable to very acceptable. The options were scored as 0-10, with lower scores indicating stronger anti-tobacco attitudes.

What do you think of the tobacco industry?

The statement has 11 options from very bad to very good. The options were scored as 0-10, with lower scores indicating stronger anti-tobacco attitudes.

1. If your good friend passes you an EC, will you use it?
2. Do you think you will use EC within the next 12 months?
3. If your good friend passes you an HTP, will you use it?
4. Do you think you will use HTP within the next 12 months?

All the statements have 5 options from definitely yes to definitely not. Responses were dichotomised as a binary outcome, students who chose "definitely not" for both items were deemed not susceptible to a specific smoking product and otherwise susceptible.

1. Tobacco industry uses many tactics to resist tobacco control regulations.
2. Tobacco industry struggles to build a corporate image to improve tobacco products sales.

Both statements have 5 options from strongly disagree to strongly agree. The options were scored as 1-5, with higher scores indicating stronger TID beliefs.

1. HTPs contain many carcinogens.
2. ECs are less harmful than cigarettes.
3. Secondhand aerosols of ECs and HTPs are less harmful.

All the statements have 5 options from strongly disagree to strongly agree. The options were scored as 1-5 or 5-1, as appropriate, with higher scores indicating better knowledge.

1. Do you think trying a few puffs of ECs will harm your health?
2. Do you think trying a few puffs of HTPs will harm your health?

Both statements have 11 options from not harmful at all to very harmful. The options were scored as 0-10, with higher scores indicating stronger anti-tobacco attitudes.

1. Do you think it is acceptable for primary school students to try a few puffs of ECs?
2. Do you think it is acceptable for primary school students to try a few puffs of HTPs?

Both statements have 11 options from very unacceptable to very acceptable. The options were scored as 0-10, with lower scores indicating stronger anti-tobacco attitudes.

What do you think of the tobacco industry?

The statement has 11 options from very bad to very good. The options were scored as 0-10, with lower scores indicating stronger anti-tobacco attitudes.

1. If your good friend passes you an EC, will you use it?
2. Do you think you will use EC within the next 12 months?
3. If your good friend passes you an HTP, will you use it?
4. Do you think you will use HTP within the next 12 months?

All the statements have 5 options from definitely yes to definitely not. Responses were dichotomised as a binary outcome, students who chose "definitely not" for both items were deemed not susceptible to a specific smoking product and otherwise susceptible.