JavaScript is a programming language for interactive clientside functionalities in web applications. It is a sequential pro- gramming language, so it cannot take advantage of multicore processors. Previously Thread-Level Speculation has been used to take advantage of multicore processors for JavaScript execution in web applications with promising results execu- tion time wise, but with a large memory overhead. In this study we have evaluated the effects of limiting the amount of memory, the number of threads and the depth of specula- tion in Thread-Level Speculation. Our results indicate that we can tune these parameters to improve execution time and reduce the memory overhead.