gistfile1.txt

var i = 0;
var newplaceholders = new Array();
var oldplaceholders = new Array();
$("input[type=password]").each(function() {
    oldplaceholders.push('#' + $(this).attr('id'));
    var passwordvalue = $(this).attr("placeholder");
    var passwordplaceholder = "passwordplaceholder" + i;
    $(this).after('<input id="passwordplaceholder' + i + '" type="text" value=' + passwordvalue + ' autocomplete="off" class="pure-input-1"/>');
    newplaceholders.push('#' + 'passwordplaceholder' + i);
    $(newplaceholders[i]).show();
    $(oldplaceholders[i]).hide();
    i++;
});

$(newplaceholders[0]).focus(function(){
    $(newplaceholders[0]).hide();
    $(oldplaceholders[0]).show();
    $(oldplaceholders[0]).focus();
});

$(oldplaceholders[0]).blur(function(){
    if($(oldplaceholders[0]).val() == '') {
        $(newplaceholders[0]).show();
        $(oldplaceholders[0]).hide();
    }
});

$(newplaceholders[1]).focus(function(){
    $(newplaceholders[1]).hide();
    $(oldplaceholders[1]).show();
    $(oldplaceholders[1]).focus();
});

$(oldplaceholders[1]).blur(function(){
    if($(oldplaceholders[1]).val() == '') {
        $(newplaceholders[1]).show();
        $(oldplaceholders[1]).hide();
    }
});

$(newplaceholders[2]).focus(function(){
    $(newplaceholders[2]).hide();
    $(oldplaceholders[2]).show();
    $(oldplaceholders[2]).focus();
});

$(oldplaceholders[2]).blur(function(){
    if($(oldplaceholders[2]).val() == '') {
        $(newplaceholders[2]).show();
        $(oldplaceholders[2]).hide();
    }
});

<input type=password placeholder=xxxx>
<script>
if(document.all){
  alert('升级浏览器好不好？')
}
</script>