Para que o visitante possa mudar a cor do fundo da página use o código
Color changer
<title> Color changer</title> <script language="JavaScript"> <!-- hiding function newbg(thecolor) { document.bgColor=thecolor; } // End --> </script> </head> <body> <div align="center"> <form> <input type="button" value="" onclick="newbg('#ff0000');" style="color: #FF0000; border: 1px solid #FF0000; background-color: #FF0000"> <input type="button" onclick="newbg('#000000');" style="color: #000000; border: 1px solid #000000; background-color: #000000"> <font color="#003399"> <input type="button" onclick="newbg('5c6390');" style="border: 1px solid #5C6390; background-color: #5C6390"></font> <input type="button" onclick="newbg('#003399');" style="color: #003399; border: 1px solid #003399; background-color: #003399"> </form> </div>
<~ Voltar