def _is_javascript_scheme(s):
    if _is_image_dataurl(s):
        return None
    return _is_possibly_malicious_scheme(s)
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.