code: func checkCandidateSrcset(l *absurllexer) {
  	q := l.consumeQuote()
  	if q == nil {
  		// srcset needs to be quoted.
  		return
  	}
  
  	// special case, not frequent (me think)
  	if !bytes.HasPrefix(l.content[l.pos:], relURLPrefix) {
  		return
  	}
  
  	// check for schemaless URLs
  	posAfter := l.pos + relURLPrefixLen
  	if posAfter >= len(l.content) {
  		return
  	}
  	r, _ := utf8.DecodeRune(l.content[posAfter:])
  	if r == '/' {
  		// schemaless: skip
  		return
  	}
  
  	posEnd := l.posAfterURL(q)
  
  	// safe guard
  	if posEnd < 0 || posEnd > 2000 {
  		return
  	}
  
  	if l.pos > l.start {
  		l.emit()
  	}
  
  	section := l.content[l.pos : l.pos+posEnd+1]
  
  	fields := bytes.Fields(section)
  	for i, f := range fields {
  		if f[0] == '/' {
  			l.w.Write(l.path)
  			l.w.Write(f[1:])
  
  		} else {
  			l.w.Write(f)
  		}
  
  		if i < len(fields)-1 {
  			l.w.Write([]byte(" "))
  		}
  	}
  
  	l.pos += len(section)
  	l.start = l.pos
  
  }
docs: // handle URLs in srcset.