xxxxxxxxxx<html><head><style> [lang|=en] { color:blue; }</style></head><body> <h2>适用于:</h2> <p lang="en">你好!</p> <p lang="en-us">嗨!</p> <p lang="en-gb">小明!</p> <hr> <h2>不适用于:</h2> <p lang="us">嗨!</p> <p lang="no">嘿!</p></body></html>