相关疑难解决方法(0)

如何强制浏览器重新加载缓存的CSS/JS文件？

我注意到一些浏览器(特别是Firefox和Opera)非常热衷于使用.css和.js文件的缓存副本,即使在浏览器会话之间也是如此.当您更新其中一个文件但用户的浏览器继续使用缓存副本时,这会导致问题.

问题是:在更改文件时,强制用户浏览器重新加载文件的最优雅方法是什么？

理想情况下,解决方案不会强制浏览器在每次访问页面时重新加载文件.我会发布自己的解决方案作为答案,但我很好奇,如果有人有更好的解决方案,我会让你的投票决定.

更新:

在这里讨论了一段时间后,我发现John Millikin和da5id的建议很有用.事实证明,有一个术语:自动版本控制.

我在下面发布了一个新的答案,它是我原来的解决方案和John的建议的组合.

SCdF建议的另一个想法是将伪造的查询字符串附加到文件中.(一些Python代码自动使用时间戳作为伪造的查询字符串由pi提交.).但是,有一些关于浏览器是否会使用查询字符串缓存文件的讨论.(请记住,我们希望浏览器缓存文件并在以后的访问中使用它.我们只希望它在更改后再次获取文件.)

由于不清楚伪造的查询字符串会发生什么,我不接受这个答案.

javascript css caching auto-versioning

Kip*_*Kip

2019 05-14

957
推荐指数

26
解决办法

38万
查看次数

如何在JavaScript中检测互联网速度？

如何创建一个能够检测用户上网速度并在页面上显示的JavaScript页面？像"你的网速是?? ?? ?? Kb/s".

javascript download-speed

Sha*_*our

2018 04-22

200
推荐指数

9
解决办法

16万
查看次数

如何强制Web浏览器不缓存图像

背景

我正在为两个无偿网站编写和使用一个非常简单的基于CGI(Perl)的内容管理工具.它为网站管理员提供HTML表单,用于填写字段(日期,地点,标题,描述,链接等)的事件并保存.在该表单上,我允许管理员上传与事件相关的图像.在显示表单的HTML页面上,我还显示了上传图片的预览(HTML img标签).

问题

当管理员想要更改图片时,会发生此问题.他只需点击"浏览"按钮,选择一张新照片然后按确定即可.这很好用.

上传图像后,我的后端CGI处理上传并正确地重新加载表单.

问题是显示的图像没有刷新.即使数据库保存正确的图像,仍会显示旧图像.我已将其缩小到图像在Web浏览器中缓存的事实.如果管理员点击Firefox /资源管理器/ Safari中的RELOAD按钮,则所有内容都会刷新,并且只会显示新图像.

我的解决方案 - 不工作

我试图通过写一个过去很远的日期的HTTP Expires指令来控制缓存.

Expires: Mon, 15 Sep 2003 1:00:00 GMT

Run Code Online (Sandbox Code Playgroud)

请记住,我在管理方面,我并不关心页面是否需要更长时间才能加载,因为它们总是过期.

但是,这也不起作用.

笔记

上传图像时,其文件名不会保留在数据库中.它被重命名为Image.jpg(在使用时简单地说出来).使用新图像替换现有图像时,名称也不会更改.只是图像文件的内容发生了变化.

网络服务器由托管服务/ ISP提供.它使用Apache.

题

有没有办法强制Web浏览器不缓存此页面中的内容,甚至图像？

我正在使用数据库实际"保存文件名"的选项.这样,如果图像被更改,IMG标签的src也将改变.但是,这需要在整个站点进行大量更改,如果我有更好的解决方案,我宁愿不这样做.此外,如果上传的新图像具有相同的名称(例如图像有点照片并重新上传),这仍然无效.

html caching image image-caching browser-cache

Phi*_*sse

2013 06-06

115
推荐指数

8
解决办法

19万
查看次数

有没有办法强制浏览器刷新/下载图像？

我有一个问题,用户报告他们的图像没有上传,旧图像仍在那里.仔细观察后,新图像就在那里,它们与旧图像的名称相同.我在上传时做的是我为了SEO目的重命名图像.当他们删除图像时,旧索引变为可用并被重用.因此它具有相同的图像名称.

有没有办法(我想可能有一个元标记)告诉浏览器不使用它的cahce？

更好的答案是将图像重命名为全新的.我将继续努力,但同时我在处理更大的问题时是快速的解决方案.

html browser image-caching browser-cache

uri*_*ium

2013 06-06

42
推荐指数

4
解决办法

7万
查看次数

如何清除或替换缓存的图像

我知道有很多方法可以防止图像缓存(例如通过META标签),以及一些很好的技巧来确保每个页面加载时显示当前版本的图像(例如image.jpg？x = timestamp ),有没有办法在浏览器缓存中实际清除或替换图像,以便上述两种方法都不是必需的？

例如,假设页面上有100个图像,这些图像被命名为"01.jpg","02.jpg","03.jpg"等.如果图像"42.jpg"被替换,则是有没有办法在缓存中替换它,以便"42.jpg"将在连续页面加载时自动显示新图像？我不能使用META标记方法,因为我需要永久性地将ISN"T替换为保持缓存,并且我不能使用timestamp方法,因为我不希望每次页面都重新加载所有图像负载.

我绞尽脑汁在互联网上寻找一种方法(最好是通过javascript),但没有运气.有什么建议？

javascript caching replace image

作者

2014 03-20

36
推荐指数

7
解决办法

8万
查看次数

JavaScript:如何强制Image()不使用浏览器缓存？

如果我在浏览器中手动加载nextimg URL,则每次重新加载时都会显示新图片.但是这段代码在每次迭代时显示相同的图像draw().

如何强制myimg不被缓存？

<html>
  <head>
    <script type="text/javascript">
      function draw(){
        var canvas = document.getElementById('canv');
        var ctx = canvas.getContext('2d');
        var rx;
        var ry;
        var i;

        myimg = new Image();
        myimg.src = 'http://ohm:8080/cgi-bin/nextimg'

        rx=Math.floor(Math.random()*100)*10
        ry=Math.floor(Math.random()*100)*10
        ctx.drawImage(myimg,rx,ry);
        window.setTimeout('draw()',0);
      }
    </script>
  </head>
  <body onload="draw();">
    <canvas id="canv" width="1024" height="1024"></canvas>
  </body>
</html>

Run Code Online (Sandbox Code Playgroud)

javascript caching image

Mar*_*son

2012 07-13

10
推荐指数

3
解决办法

3万
查看次数

在Chrome中操作图像时内存泄漏

我在Chrome中遇到了以下2(巨大的!)内存泄漏:

使用新字节编辑现有图像的'src'时
使用clone()克隆图像时

请注意,在Internet Explorer中没有任何内存泄漏!

一些背景:我正在开发一个项目,其中外部摄像头提供图像的实时馈送(假设每秒100帧).

该项目的主要3个功能是:

玩现场直播
记录实时馈送
显示录制的Feed

欢迎您下载以下独立代码(只需将其保存为"leak.html"并执行),并亲眼看看:

<!DOCTYPE html>
<html>
    <body>
        <canvas id="meCanvas" width="526" height="395"></canvas>

        <script src="http://code.jquery.com/jquery-2.0.3.min.js" type="text/javascript"> </script>
        <script>
            var meContext = document.getElementById("meCanvas").getContext("2d");

            // Bytes array representing a chair image
            var chairImgSrc = 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SMzTYftGoQx9i3Nd6owAB2rK0bw1LY3JmmlQ8YAWt9bPP8AH+lTKLHGSK9LVo2aqOZMfhVZ0MZ579DUuLRaaYA0ZpuaXNSMdmg802lzTELmjtSCjNAx2actMzSg4oEZmeKOtFJTICijqaKBhmikooBBRRRQMXrRSUUAFFFFAC0lAooGLRSZooAXOKTJpaKBgM0UmaWgAooooAM0UlFAC0ZpKKACikzRQAUhNFIaBjSaaaU000CEJpppTTCaBiGmE8U5qYaBDSajOTTyKYaAET74zVkVWX74qyKYhwpwptKKQEgpwpopRQMw9ZObz6KKzqv6qc3r/hVCqTuiWrMR+lOtnxkUxjk4pIThjTQjWLZUGomakVv3Y+lMJpiAmmE0pNNJpDDrT1iY9qgMuw5HWkN3J/epiLq27GlFgW6sKo/apf75/Omm4kOcu350aD+Z0GmILCYyAqxIxz2rVGpr/FLGv41xBlJ6k0m6k0gTsdwdUgX71wn4NTDrdoOtwPwrit/vRu96SG2jsT4gsh/y1Y/8BNNPiOyHeQ/8BrkN/vSb/endEnXHxPafwrIfwph8UW4PEUh/KuU3j1pd1F2PTsdSfFUY6QN+dN/4S0jpaj/vquY3U4ZPQE0+YVkdJ/wl8o6Wqf8AfVH/AAmFz/z7RD8Sa5s5HUEUKS5CqCSegFHMCVjpD4vvD92OEfgajPirUHP31Uf7K1lppl4/S3f8Rip10S+bpDj6kUuaw/iOg03WHmI81yxPUk1uNNG8YDMMetcjZaPexvlyiD65rcgtfKHzuXb1NOU1YXLqW6M0wGlzWRoOBopueaXNIBwNFNzRmmA7NLmmZozQIz+9LSCimSLSUtJmgApKWkzQAUUUlMYtLSUGkMKKTNLTAKKTNGaQDqAaSigBaKSjNAC0UlJQA7NJmkNFAxaM0lFAC0ZpKM0DDNFFJmgAzTTTjTTQIaaaaU000DENNNKaaaAGtTO1ONNNAhpphpxppoARfvirAqsv3hVkUCH0opopwoGPFOFMFPFAGFq6bbsn1ANZ9bGtJxG/4VjMcA1S2JYw8saah+egHrTV+9QSaCt+7FITTVb5RSE1QCk0maaWpM0gGsm49ab5XvUmaQmgBhT3qxY6dJfymKLGQMknpUGa6vw5Z+RZmZxh5P5UnoNanMX+m3OnOqzqMN91lOQapZNegarax3enyo+AQMgnsa4FlwSKSdwasM5o5p1FMQ2loooAcqs7BVBLHoBW/Y6EIrSS7vgQFUlU/wAaqeHLfz9VQ9oxuNb/AIkuPJ0wp3kO2k30Q4o452yxI4FSw3BiFQHk0maYmWJ7gyjHareh2/2jUohjIQ7jWaK6bwrb4864x1+UH+dAHR0opKKzNBc0ZpKMmmAueaXNNpQaQC9KXNNzRmmA7NKDTM0uaQh1FN3Umc0wKdFFFMmwUlGaKAEo70GimAUUUmaBi0ZpKM0WAWkoooGLQKSigBaBQaKQBRRRQAUUlFAC0UlFAwooNFAAKKKKAA0lFJQMWmk0tNJxQAhphpxppoAQ000pNNNAhpphp5phoAaaaacaYaAEX7wqyKrL94VZFADqcKaKcKAHU4U2nCgCnqke+zY/3ea5yTgV1lwnmW8ieorkpvvYpoljAcKaanL0rcKKIh82aZJbzgCmk0hNNJpgLmk3U0mk3UAOzQWqMtRyaQFuwtjeXccQHBPzH0Fd1GojjVF4CjAriNOv309naNFZ2GMt2q6+v3j9GVfoKTTZUbG7rU3k6VOc8su0fjXCt1rQvtRubmIJNKWXOcVnGhKwN3CkopM0yQpaSlHWgDqPCdviOWf+8do/CofFVxvuY4M8IuT+NV7G8ntbcJE5VeuKiuv9KlMkp3Oepo5bu407Iys80Zq4bZfSmG2FOwiBa7nRbf7PpsS45Ybj+NcesABBPIFdFDr4VVUw4AGODSadtBrc3aOlZa65CRyjA1Ius2xPVh9RUWZWxoZozVRdStn6SD8alW5ibpIp/GgZNS5qMOD0IP407NADqAabS5pALRnNNpfwoEFFGCeAKkWB26KaY9ChRRRTIAikpabQApNJSmkpjCikJozQAtJRRQMWikozQIWikozQMWjNJRSGLmjNJRQIWikooGLSUUUAFFFGaAAmikooAKKTNFABSGjNJ1oGNNITSmkNAhppppTTTQA00004000ANNMNONNNACL94VZFVh94VZFADhS00U4UAOFOFNFOFAC9q5K8iMV3IrdmP5V1tc/rce283/3lFNCZkyHmnw9M1ExyalU4WmQSFqYWppbNN5agBS9AyetKEp4SgBAuaeFpQtOAp2AQLTwKUCl7UwK07c4qHNOlOXNMUE9KkAJpKcVYdRTKAFp8Y3SAUyp7Nd0oPpQBoqPlFBFLiirEMIpNtSYpMUgGbacFp2KMUwAU4UnSnCgAyRShjSUtAXJEnkUfK5H0NTpqFwp4lb8aqilosO7NKPV5RgMoartvqcMpAc7CfXpWBmnBsUuVBc7aCzWVAyyKVPcGp1tYE+82a4u2vJrZsxSFR3GeDW/ZX63aejjqKlxsNO5rebBGPlXNMa69ABVQv71G0yjqRUjsin2opB0ooAKSiimIOlJRRQMOtJS0lAC0lJS4oGFFJRmgBaKTNHWkAtLmkpKAHUmaKKACjNJmigYuaKTNFAC0UlFAC0lFFACUUGigYlB6UUlACGm04000ANNNNONNNAhpphpxppoGNNNNONNNAho+8KtCqmeRVodKAHCnCmU4UAOFOpopaAHCub1ifzbtsHIX5RW/cS+RbvIf4RXIzvuYk9Sc00KRGOWpzN2FMB5qVVpkDVQ1Iq05Vp4WmA0LTwtKFp4WnYBAtKFpwFKBQAgFI/yoTTxUN02I6AKXUmtqxtYkhDMoLHnJrDBwa17G8UxhGOCKkaLF1aRSxkqArAdu9YUg2sRW1PcrGhOaxJG3OTQNobmr1gnBaqIrUtExCPemiSeilxRiqEJRS4ooASlxRRQAoooFFABS0UUCFopKUUDFooozTAdmpbe4aGQMpwRUGaOlAXN9JjOgYOcH0o8vPvVPSphuMTHr0rWEY7VzyTTNou6K9HWk6UtUQIaM0UlMApKCcUh5oAO9FFGaACikooGLmim5pc0gCjNJRmmAuaXNNzRSAWjNFFAwooooELRRSZoGLRRSZoAKKKM0AFFJRQAUneg0lAwppp1NNADTTTTjTTQIaaaaU000ANNMNPNNNADAPmFWh0qrj581aXpQA4UopKUUAOpRSUvagDL1u42xLEOrcmuec8mtDUrjz7l2zwPlFZrcmqIYJyasLUQwBTwaBE4pwqINTwwNMCUU4CowacDTAfSim5pQaYh9U71uQKtZrPuW3SGkxkRpM4opDUgOZ2PUmm5pKKAHRjc4FbUYwgHpWVZrunHtWsKpCYtLmkopgLmikpaADFFLRQAUYoFGaADFLRRmgQUUtJQADrS0UmcUxgaTNKTTaQE0EhjlVh2NdPCu5FZScEZrkxxXTaM5lsl5ztOKzqLqXBkZoooNIApKKSgA70lBopgFJRSUAGaM0lGaADNFFJmkAtFFFAwpRSUtAxaKKKBBRRRQMKWkooEGaKKSgYUUUUAFJRRQAUlBpKBhSdaCaSgBDTDTzTDQA0000pptAhDTTSmkoAb3qyOlVu9WV6UAKKcKSloAUUuMikp1AHJ3sZjmdT6mofs7bN+DgV01xpkNzKZGyCfSnT2CNYtDGMHHH1qrk2OUozilkUo5UjBB5plBI8NinCTFRUZoAsCX3pwmA71VzRmgC6JQad5tUNxFLvPrTuBeMuAeapSHLGk3k96bmkAuaQ0dqaaAFopKWgC7YLgljV8GqFuwRBVhZapMCwDS5qESCnb80xMkpajDe9OzQA6img0uaBDhSUmaUGgYuaKTNLmgBaWm5pc0xADzQaM0maQwzRSdaOlACmt/w7J+5kX0Nc+TW94cUlZSPaplsUnYkozSUZqBimkozSUABpKKKBBTaWg0xiUUUUhiUUZooELQKSlzQMKXNJRQAtLSZooAKM0UUAFHWiigAzRRSUDAmiikoAKM0UlABSGikoADSZoNNJoACaaTSk000guNNIaU000wENNNOppoEIOtWAeKr96nHQUAPFOpop1AC04U0UoNADhThTRThSGc7rOnSJO06KSjcnHasc8dRXd4B4PSqNxotrc5OzYx7rTTJaORzRmt2bww4/1MoP8AvDFVJNAvY+iBv901RJm5pM1YewuY/vQSD/gJqExuv3lI+op2sC12EJpM0YpMUgHCkpQOKSgA4pKX8aQ0AHeigUHpQA5XI4qZZSKrinA0AWhNT1m96p5pwJpgXRLTxNVENS7zRcC+JR604SVQEvNPEtFwsXg4pQ1UxL704S07gW84o3VXEtOEtAibdRuqLeDS7qYEobmjNR7qN1AEoNLmot1LuoBDjXUeG4sWbP8A3mrlA2TXZaJFs06MZ5PNZzLjuU6KTpS0gDikoNFACUUUUAJSUtJTDYKOtFJSAKKKKACiiigAzS0lFAC0tJRmgYUUUnegBaKSigBc0UlBNABQaSjtQMM0lFGaAEpCaCaaTSAM0hpaaaYCUlLSGgBKbSmmmgQhpDSmkNACd6sj7oqr3q0vSgBQadmminCgBRSikFKKAHCndqaKcKQCinCminCgB4FOVSxwBUkNs8vbFakFpHCuW607A2VbewL8v09KuyWtmiYkhjf2K0yW7C/LGKrNIXPzHNF7bCtfcrXOladOf+PKED1C4NUZvDmmlGYw7QOeCa1s1R1mfyNLnYHDFcCk5N7saVtjgJgvmNtGBk4+lR4p7ck0w1ZLExzSEUZxQORQIXAxSE8UoGatwWLXGFVTk0AUwTSjpWld6K9qiv5gINUDC654yBSTuOwlL+NJg46UYpiFpaSigB1Lnim0o5oAcCaUMab2pM0ASh8U4PUA5PNPzigCYPThJVfdShs07gWPNpRJVfdS5ouBZ83PFLuyeKrg1IvNO4Fu0iM9wka9WOK7uCDyYlQcACub8N2hMxuGX5V+79a6tGBrKT1NIrQwKM0UlMQtFJmigQGikozQAcUlBpKACg0UZoAKSjNFABRmjNANABS02loAXNGaTNFAxaKSjNIBaKSjNAC0lGaTNAC5pDRTSaYC5ppNBNIaACg0maKQwzTc0tIaAEpKCaQ0wENIaU000CEooNIaAE71aXoKq96sr0FADhTqaKWgBacKbThQA7NKKQDNW7ezaTBbgUWC9iKONpDhRWhb2OMM4/OpkjjgToOKhkuy3C/nQLVlppUhHHWqz3DSd8D0qsz9ycmlUkigdktiXNLnvUTOEGSarS3BbgcCobGlcsSXIXIXk1z3iO5Y2yJn7zc1pFjXOa7KXugvZRRHVjlojKJpuaWkrUyENANFKKAJIULyBQOSa7K0tktoQqLzjk+tczo0Jmv4/RTk11+KyqN7GkFcztVAMCjA61i+Up4rZ1k7IEIH8VY6ODzVQ+EUtzYtLCCS0UPEre+Oajm0C3c5Qsh9O1WbE+Zaqy9Ks7mHXmobdykk0c/N4enGTEysPrg1RuNOubfO+NsDv2rsA2R0pkgLKVI4IxTU31E4LocT060A1PewG3uXjPY/pVboa1M2OzSjpTRzTgpJ4oAOlLTzEwHSmbCO1ACU7NAGKMZNAC5zS+1AHFPVCTQAKDxVu0tnuJlRBkk4qax0me7YbFwvcmuq0zS4dPXON0h6saUpWGlcu2FolpaJEB0HJ96tCPPSmA1IDisjW1j/2Q==";

            var image = new Image();
            image.onload = drawNewImage;

            var RECORD_LEN = 20;
            var recordedImages = new Array(RECORD_LEN);
            var count = 0;

            function drawNewImage() {
                meContext.clearRect(0, 0, meContext.canvas.width, meContext.canvas.height);
                meContext.drawImage(image, 0, 0, meContext.canvas.width, meContext.canvas.height);

                setTimeout(nextImage, 10); // Simulates 100 frames per second …

Run Code Online (Sandbox Code Playgroud)

javascript jquery memory-leaks google-chrome image

o_c*_*o_c

2017 05-23

10
推荐指数

1
解决办法

3866
查看次数

画布上的 CORS 不适用于 Chrome 和 Safari

我正在尝试在画布上显示图像。图像托管在 S3 上。

CORS 是在 AWS 上设置的，并且在脚本中CrossOrigin设置了该属性anonymous。

在 Firefox 上一切正常——但在 Chrome 和 Safari 上无法加载图像。

错误Safari：

Access-Control-Allow-Origin 不允许Origin https://www.example.com。 http://mybucket.s3.amazonaws.com/bubble/foo.PNG

[错误] 无法加载资源：Access-Control-Allow-Origin 不允许Origin https://www.example.com。（foo.PNG，第 0 行）

跨源资源共享策略拒绝跨源图像加载。

错误铬：

CORS 策略已阻止从源“null”访问“ https://mybucket.s3.amazonaws.com/bubble/foo.PNG ”上的图像：没有“Access-Control-Allow-Origin”标头存在于请求的资源。因此，不允许访问 Origin 'null'。

CORS 配置非常标准。我尝试了<AllowedOrigin>*</AllowedOrigin>，以及其他一些变体，但没有任何区别……只有一个例外：<AllowedOrigin>null</AllowedOrigin>似乎适用于 Chrome。

AWS 上的 CORS 配置

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
<CORSRule>
    <AllowedOrigin>https://www.example.com</AllowedOrigin>
    <AllowedOrigin>http://www.example.com</AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <AllowedHeader>*</AllowedHeader>
</CORSRule>

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画布脚本

let myImage = new Image();
myImage.setAttribute('crossOrigin', 'anonymous');

myImage.src = thisDocument.url;
myImage.onload = function() {
  canvas = document.getElementById('myCanvas'); …

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safari google-chrome canvas amazon-s3 cors

Kai*_*Kai

lucky-day

7
推荐指数

1
解决办法

2339
查看次数

为角度应用程序缓存资产文件夹中的静态文件（图像、pdf、png 等）？

我们的应用程序是使用 angular-cli（版本：7.0.2）和 angular（版本：7.0.0）开发的。我们的图像文件很少，pdf 保存在资产文件夹中。每 3 个月发布一次应用程序的每个版本，这些文件都会发生变化。

为资产文件夹中的所有文件实现缓存破坏的最佳方法是什么？
是否有一种通用技术可以添加到客户端应用程序以在访问时加载资产文件夹中所有文件中的最新文件？webpack.config.js（使用angular-cli工具创建项目时生成的文件）中是否可以添加任何配置？

我通读了此链接中提到的各种技术：使用同一网址中的新图片刷新图片

不确定哪个是最好的解决方案。任何关于如何实现缓存破坏的建议/代码片段表示赞赏。

browser-cache webpack angular-cli angular angular7

use*_*903

lucky-day

6
推荐指数

1
解决办法

3454
查看次数

如何防止浏览器图像缓存？

防止浏览器在PHP中缓存图像的最佳方法是什么？

我试过了标题(方法:

header("Expires: Tue, 03 Jul 2001 06:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

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但是,除非手动清除浏览器的缓存,否则似乎无效.

我的图像被替换为相同的名称,例如avatar.png作为用户的可更新头像,但是当它被更新时,浏览器保持旧版本.

即使删除原件并添加新原件,浏览器仍然保留旧的avatar.png.

有什么想法吗？

php caching image

k_s*_*sel

lucky-day

5
推荐指数

2
解决办法

2万
查看次数