A script evaluator analyzes script code and identifies possible problems with respect to given browsers and given browser versions. When configuring the parameters of analysis of the script evaluator, the user may select versions of known browsers for which support is desired. The script evaluator may point out functions in the script code that are not supported by certain versions of selected browsers. The evaluator may also suggest alternative functions that may be supported by all desired browser versions. Help information may be provided to assist the user. The script evaluator may receive browser support and help information from a library. The library may be collected from the browser software vendors or may be supplied with the script evaluator. The script evaluator may also include an editor or may be part of an existing developer tool.