這個方法 超好用的，給大家做個參考
/*模仿輸入框被disable時的效果*/
.disable_input {
font-size:
9pt;
filter:alpha(opacity=0); /* IE */
-moz-opacity:0.3; /* Moz +
FF */
opacity: 0.3;
}
/*還原輸入框被disable時的效果*/
.enable_input
{
font-family: "Geneva", "Arial", "Helvetica", "san-serif";
font-size: 9pt;
color: #666666;
text-decoration: none
filter:alpha(opacity=100); /* IE */
-moz-opacity:1; /* Moz + FF */
opacity: 1;
}