IE7 IE 8 對文字框的  placeholder 屬性不支援

提出一種解決方案

//**前提 需引用 jquery.js檔案

<script type="text/javascript">

$(function(){

       handlePlaceholderForIE();

});

 function handlePlaceholderForIE() {
            // placeholder attribute for ie7 & ie8
            if (jQuery.browser.msie && jQuery.browser.version.substr(0, 1) <= 9) {

                // ie7&ie8
                jQuery('input[placeholder], textarea[placeholder]').each(function () {
                    var input = jQuery(this);
                    jQuery(input).val(input.attr('placeholder'));
                    jQuery(input).focus(function () {
                        if (input.val() == input.attr('placeholder')) {
                            input.val('');
                        }
                    });
                    jQuery(input).blur(function () {
                        if (input.val() == '' || input.val() == input.attr('placeholder')) {
                            input.val(input.attr('placeholder'));
                        }
                    });
                });
            }
        }

</script>

<input    type="text" id="txt"  placeholder="請輸入您的賬號"     autocomplete="off"" />