鼠标经过图片变暗的js兼容IE FIREFOX

js部分：

function dentro(valor) {
valor.style[‘opacity’] = 60 / 100;
valor.style[‘-moz-opacity’] = 60 / 100;
valor.filters.alpha[‘opacity’] = 60;
}
function fuera(valor) {
valor.style[‘opacity’] = 100 / 100;
valor.style[‘-moz-opacity’] = 100 / 100;
valor.filters.alpha[‘opacity’] = 100;
}

网页部分：

<img src=”” alt=”Muestra” border=”0″ style=”filter: Alpha(opacity = 100)” onmouseout=”fuera(this)” onmouseover=”dentro(this)”/>