ie下placeholder解决办法

! function(window, document, $, undefined) {
    var target, i = 0,
        len, tmpPh;
    if ('placeholder' in document.createElement('input')) return;
    target = $('[placeholder]');
    for (len = target.length; i < len; i++) {
        tmpPh = target[i].getAttribute('placeholder');
        target[i].value = tmpPh;
        target[i].style.color = '#aaaaaa';
        target[i].onmouseover = function() {
            if (this.value != this.getAttribute('placeholder')) return;
            this.value = '';
            this.style.color = '#000000';
        }
        target[i].onblur = function() {
            if (this.value != '') return;
            this.value = this.getAttribute('placeholder');
            this.style.color = '#aaaaaa';
        }
    }
}(window, document, jQuery); 

<input type="text" placeholder="请输入你的名字">
<hr>
<input type="text" placeholder="aaa">
<hr>
<input type="text" placeholder="bbb">