Procedure
All communication between the research agency and the participants took place on the web via WhatsApp. The day before the study was launched (day 0), the research agency distributed data packages to each of the participants to cover internet data costs incurred. Participants completed web-based self-report questionnaires hosted on Qualtrics at 3 time points, that is, baseline (day 1), 1 day after the intervention (day 9), and 1 month after the intervention (day 36). The items in the closed questionnaires were not randomized. Adaptive questioning was used only for the consent question at the beginning of each questionnaire. The questionnaires contained an average of 34 (SD 3.77) screens with 4 to 5 items per page. A “Back” button was included so that participants had the option of reviewing and changing their responses. Questionnaire functionality was tested and verified by the authors (KMG and SH) before sharing the Qualtrics links with the research agency.At 8 AM (Coordinated Universal Time +7) on days 1 (time 1, baseline [T1]), 9 (time 2, 1 day after the intervention [T2]), and 36 (time 3, 1 month after the intervention [T3]), the research agency sent participants a link to the corresponding questionnaire as well as their unique participant identification number (PIN), which participants entered at the beginning of each questionnaire. The participants had 24 hours to complete each self-report assessment. Reminder messages were sent to participants who had not completed the questionnaire within the first 8 hours (these prompts will not be used or available when the intervention is disseminated on social media). Demographic information was collected using the baseline questionnaire.After the participants completed the baseline questionnaire, a researcher not involved in this project was concealed from participant information and condition and generated the allocation sequence (based on a block design) using an automated web-based randomizer [Participants randomized to the intervention condition were sent their PIN and a Qualtrics link with one video and its associated activities on days 3 to 8 at 8 AM (Coordinated Universal Time +7). Included in each link were state measures of body satisfaction and mood to be completed immediately before and after each of the intervention’s videos. Participants had 24 hours to engage with each link (ie, watch the video and complete its associated web-based activities), with reminder messages sent to those who had not engaged with the intervention after 8 hours. Acceptability information was obtained from the intervention group participants at the end of the day 9 questionnaire.The day after the final questionnaire (day 37), all participants received a certificate of participation and debrief document that outlined the study’s objective, included contacts for mental health support, and were provided a link to access the intervention video series. Thereafter, incentives of Rp 125,000 (approximately US $8.75) were given to participants who completed all 3 questionnaires. Winners of the “Your Own Words” activities were awarded their prize within 2 weeks of trial completion. As specified in the trial protocol [