jQuery等同于PHP的file_exists()? [英] jQuery equivalent of PHP's file_exists()?
本文介绍了jQuery等同于PHP的file_exists()?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在下面的代码段中,从我的jQuery设置中,我需要检查图像文件是否实际存在,如果不存在,我想替换默认图像.目前,如果文件不存在,我会得到一个损坏的图像占位符...
In the code snippet below, from my jQuery setup, I need to check if the image file actually exists and if not, I'd like to substitute a default image. Currently if the file does not exist, I just get a broken image placeholder...
$('#myTheme').change
(
function()
{
var myImage = $('#myTheme :selected').text();
$('.selectedImage img').attr('src','../wp-content/themes/myTheme/styles/'+myImage+'/screenshot.jpg');
//if screenshot.jpg does not exist, use "../../default.jpg" instead
}
);
推荐答案
听起来您需要访问HTTP响应标头.这是我在互联网上找到的一段代码.
It sounds like you need access to the HTTP response headers. Here's a piece of code I found on the Internet.
来源: http://www.vfstech.com/?cat=1
$(document).ready(function() {
var ajaxSubmitOptions = {
// the normal success callback is not used
// success: function (responseText) {
// ...
// } ,
complete: function (xhrObj, status) {
if(status == "error") { // 500 server error?
alert("There was an error processing this request.");
} else {
if (xhrObj.getResponseHeader("X-My-Custom-Header") != "") {
alert("Intercepted special HTTP header...");
alert(xhrObj.getResponseHeader("X-My-Custom-Header"));
}
else {
// call the function you normally would have used in the "success" callback:
this._success(xhrObj.responseText);
}
}
} ,
_success: function (responseText) {
alert("Normal success callback...");
alert(responseText);
}
};
$('#myForm').ajaxForm(ajaxSubmitOptions);
})
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