Evaluating an Ascii Math problem in javascript

Question

I am working on a web-based project to take images of math problems and evaluate them. The OCR I use to retrieve the math problems from the images only outputs LaTeX or Ascii Math (Currently using ASCII math), and I need to find a way to evaluate these problems.

For example, if I have

1(1)/(5)-:-1(1)/(3)

Then instead of displaying it, I would like to evaluate it. I have tried the evaluatex library, but I keep encountering an error with it:

VM2650 evaluatex.min.js:1 Uncaught Lexer error: can't match any token.

If anybody could point me to a better library, or tell me how to fix this error, that would be a great help.

Here's what I tried (In the chrome developer console):

evaluatex("(-1)/(5)-:(-1)/(3)")();

Thanks!