var doc = window.document, input = doc.createElement('input ');
if( typeof input['placeholder'] == 'undefined' ) // 如果不支援placeholder屬性
{
$('input').each(function( ele )
{
var me = $(this)
var ph = me.attr('placeholder');
if( ph && !me.val() )
{
me . val( ph).css('color', '#aaa').css('line-height', me.css('height'));
}
me.on('focus' , function( )
{
if( me.val() === ph)
{
me.val(null).css('color', ''); }
}).on('模糊', function()
{
if( !me.val() )
{
me.val(ph).css('color ', ' # aaa').css('line-height', me.css('height'));
}
});