code: public Elements getElementsByAttributeValueStarting(String key, String valuePrefix) {
          return Collector.collect(new Evaluator.AttributeWithValueStarting(key, valuePrefix), this);
      }
docs: Find elements that have attributes that start with the value prefix. Case insensitive.
  
  @param key name of the attribute
  @param valuePrefix start of attribute value
  @return elements that have attributes that start with the value prefix