La cadena original es:<b>ˇHOla Mundo, mundoo, mundoooOo!</b><br />Sustituiremos: <b>o</b> por: <b><span style='color:red;background-color:yellow'>o</span></b><br>El resultado será: <b>ˇH<span style='color:red;background-color:yellow'>o</span>la Mund<span style='color:red;background-color:yellow'>o</span>, mund<span style='color:red;background-color:yellow'>o</span><span style='color:red;background-color:yellow'>o</span>, mund<span style='color:red;background-color:yellow'>o</span><span style='color:red;background-color:yellow'>o</span><span style='color:red;background-color:yellow'>o</span><span style='color:red;background-color:yellow'>o</span><span style='color:red;background-color:yellow'>o</span>!</b>