Mensagem Na Caixa de Texto

<div dir="ltr" style="text-align: left;" trbidi="on"><script language="JavaScript"> <!-- function Menu1(form) { form.TXTVal.value="seu texto 1";}function Menu2(form) { form.TXTVal.value="seu texto 2"; }function Menu3(form) { form.TXTVal.value="seu texto 3"; }function Menu4(form) { form.TXTVal.value="seu texto 4"; } function Menu5(form) { form.TXTVal.value="seu texto 5"; } // --> </script><br /> <div align="center"><form><br /> <br /> <input onclick="javascript:alert('sua mensagem.')" onmouseover="Menu1(this.form);" style="background: #1e90ff; color: black; font-size: 8pt; font-style: verdana; font-variant: normal;" type="button" value="texto 1" /><input onclick="javascript:alert('sua mensagem.')" onmouseover="Menu2(this.form);" style="background: #1e90ff; color: black; font-size: 8pt; font-style: verdana; font-variant: normal;" type="button" value="texto 2" /><input onclick="javascript:alert('sua mensagem.')" onmouseover="Menu3(this.form);" style="background: #1e90ff; color: black; font-size: 8pt; font-style: verdana; font-variant: normal;" type="button" value="texto 3" /><input onclick="javascript:alert('sua mensagem.')" onmouseover="Menu4(this.form);" style="background: #1e90ff; color: black; font-size: 8pt; font-style: verdana; font-variant: normal;" type="button" value="texto 4" /><input onclick="javascript:alert('sua mensagem.')" onmouseover="Menu5(this.form);" style="background: #1e90ff; color: black; font-size: 8pt; font-style: verdana; font-variant: normal;" type="button" value="texto 5" /><br /> <input name="TXTVal" size="60" type="text" /></form></div></div>