Experiments are increasingly moving online (especially during the COVID epidemic). This poses a major challenge for researchers who rely on in-lab process-tracing techniques such as eye-tracking. Researchers in computer science have developed a web-based eye-tracking application (WebGazer) (Papoutsaki et al., 2016) but it has yet to see use in behavioral research. This is likely due to the extensive calibration and validation procedure (~50% of the study time) and low/inconsistent temporal resolution (Semmelmann & Weigelt, 2018), as well as the challenge of integrating it into standard experimental software. Here, we incorporate WebGazer with the most widely used JavaScript library among behavioral researchers (jsPsych) and adjust the procedure and code to reduce calibration/validation and dramatically improve the temporal resolution (from 100-1000 ms to 20-30 ms or better). We test our WebGazer/jsPsych combination with a decision-making study on Amazon MTurk. We find little degradation in spatial or temporal resolution over the course of the ~30-minute experiment. We replicate previous in-lab findings on the relationship between gaze dwell time and value-based choice. In summary, we provide an open-source, accessible, software template and tutorial for web-based eye-tracking in behavioral research that is sufficient to replicate in-lab studies with just a modest number of participants (N=38), and that is orders of magnitude faster than in-lab data collection. Moreover, we highlight that web-based eye-tracking is a useful tool for all behavioral researchers, as it can be used to ensure that study participants are humans and not machines.