Well I wanted everything else to stay in place, so the .hide() in jQuery didn't work because this is equivalent to adding the following class in CSS

.hide{
display: none
}

Also, I didn't want any form of animation so the .animate() and changing the opacity from 0 to 1 isn't what I am looking for. I have tried it and I can see the element fade out. I want it to disappear instantly without all the others in the page move.
I decided to use the .css( propertyName, value )

function hideLastSaved(form){
    jQuery(' [name="lastSave"]').css('visibility','hidden');
}

function showLastSaved(form){
    jQuery(' [name="lastSave"]').css('visibility','visible');
}

which is the shorter way of adding a class like this one:

.hider{
visibility: hidden
}

to the element using

function hideLastSaved(form){
    $(' [name="lastSave"]').addClass('hider');
}

function showLastSaved(form){
    $(' [name="lastSave"]').removeClass('hider');
}

similar to what Jamie Dixon suggests.
I have not tried what Nightw0rk suggests:

function hideLastSaved(){
    jQuery(' [name="lastSave"]').css('opacity','0');
}

function showLastSaved(){
    jQuery(' [name="lastSave"]').css('opacity','1');
}

but will try it just so I know how it looks like.
Thank you all very much for your brilliant suggestions!

hide方法会将项目的display属性变更为none。
如果要在隐藏元素的同时保持其位置，请添加一个将visibility设置为hidden的类。

CSS格式：

.hider{
   visibility:hidden;
}

JS

function hideLastSaved(form){
    $(' [name="lastSave"]').addClass('hider');
}

function showLastSaved(form){
    $(' [name="lastSave"]').removeClass('hider');
}

下面是一个非常基本的演示：http://jsfiddle.net/dWw7F/

请尝试更改css的visible属性。

function hideLastSaved(){
    jQuery(' [name="lastSave"]').css('opacity','0');
}

function showLastSaved(){
    jQuery(' [name="lastSave"]').css('opacity','1');
}

使用下列程式码变更span的可见性：

$('#uniqueSpanId').animate({opacity: 0.0});

这会将uniqueSpanId范围的不透明度更改为0，使其不可见。执行相反的命令即可将其更改回来：

$('#uniqueSpanId').animate({opacity: 1.0});

另一个道：

function hideLastSaved(form){
    jQuery(' [name="lastSave"]').css('display','none');
}

function showLastSaved(form){
    jQuery(' [name="lastSave"]').css('display','block');
}

jQuery hide() =设置display: none和visibility: hidden，带过渡
jQuery show() =设置display: block和visibility: visible，带过渡

如果您使用的是旧版本的JQuery，请使用以下代码：

function hideLastSaved(form){
jQuery(' [name="lastSave"]').fadeOut(1);
}

function showLastSaved(form){
jQuery(' [name="lastSave"]').fadeIn(1);
}

“1”只是设置了一个1毫秒的时间范围，从技术上讲，这没有什么，如果您使用的是较新版本的JQuery，那么只需添加$而不是JQuery：

function hideLastSaved(form){
$('[name="lastSave"]').fadeOut(1);
}

function showLastSaved(form){
$('[name="lastSave"]').fadeIn(1);
}