Develop Reference

Execute Script tag using JS instead of PHP

I have a case in php, where I execute <script> tag of Adsense, if the userAgent is not BOT, but for some good reason I want to execute it using JS.
Helper Function:
function detectBottypes() {
$userAgent = strtolower($_SERVER['HTTP_USER_AGENT']);
if(!empty($userAgent) and preg_match('~(bot|crawl|google|lighthouse|spider|feedparser|crawler|pinterest)~i', $userAgent)) {
return true;
}
return false;
}
in View:
#if( Request::is('photo/*') && detectBottypes()==false )
<script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js" crossorigin="anonymous">
</script>
#endif
Above, if request is photo/* and not bot then it is rendered in view, but I want it to be rendered in either of cases but only executed for the specific case.
I have the case of JS
window.onload = function () {
var agent = navigator.userAgent.toLowerCase();
if (agent.indexOf('bot') != -1) {
// ******* Execute here ********
}
else {
}
}
Reason why I want: I cache the view file to skip the load on server, so if the page is first crawled by Bot(Google) it is cached without the above case of Adsense Script ( Ad is not loaded to Bot) but since it is cached if later it is viewed by real user, the cached version without Ads is shown which I do not want, so preferred to be with JS

You can dynamically load a script with something like:
window.onload = function () {
var agent = navigator.userAgent.toLowerCase();
if (agent.indexOf('bot') != -1) {
var scriptTag = document.createElement('script');
scriptTag.src = 'https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js';
scriptTag.async = true;
scriptTag.type = 'text/javascript';
scriptTag.crossorigin = 'anonymous';
document.head.prepend(scriptTag);
} else {
}
}
This should cause the browser to download and run the script. However there's a broader question on your use of caching. It may be simpler if you cache two versions of the content and serve each one based on the UA, if that is an option.

load inserted script, making sure that libraries load first [duplicate]

I'm creating a jquery plugin and I want to verify an external script is loaded. This is for an internal web app and I can keep the script name/location consistent(mysscript.js). This is also an ajaxy plugin that can be called on many times on the page.
If I can verify the script is not loaded I'll load it using:
jQuery.getScript()
How can I verify the script is loaded because I don't want the same script loaded on the page more than once? Is this something that I shouldn't need to worry about due to caching of the script?
Update:
I may not have control over who uses this plugin in our organization and may not be able to enforce that the script is not already on the page with or without a specific ID, but the script name will always be in the same place with the same name. I'm hoping I can use the name of the script to verify it's actually loaded.

If the script creates any variables or functions in the global space you can check for their existance:
External JS (in global scope) --
var myCustomFlag = true;
And to check if this has run:
if (typeof window.myCustomFlag == 'undefined') {
//the flag was not found, so the code has not run
$.getScript('<external JS>');
}
Update
You can check for the existence of the <script> tag in question by selecting all of the <script> elements and checking their src attributes:
//get the number of `<script>` elements that have the correct `src` attribute
var len = $('script').filter(function () {
return ($(this).attr('src') == '<external JS>');
}).length;
//if there are no scripts that match, the load it
if (len === 0) {
$.getScript('<external JS>');
}
Or you can just bake this .filter() functionality right into the selector:
var len = $('script[src="<external JS>"]').length;

Few too many answers on this one, but I feel it's worth adding this solution. It combines a few different answers.
Key points for me were
add an #id tag, so it's easy to find, and not duplicate
Use .onload() to wait until the script has finished loading before using it
mounted() {
// First check if the script already exists on the dom
// by searching for an id
let id = 'googleMaps'
if(document.getElementById(id) === null) {
let script = document.createElement('script')
script.setAttribute('src', 'https://maps.googleapis.com/maps/api/js?key=' + apiKey)
script.setAttribute('id', id)
document.body.appendChild(script)
// now wait for it to load...
script.onload = () => {
// script has loaded, you can now use it safely
alert('thank me later')
// ... do something with the newly loaded script
}
}
}

#jasper's answer is totally correct but with modern browsers, a standard Javascript solution could be:
function isScriptLoaded(src)
{
return Boolean(document.querySelector('script[src="' + src + '"]'));
}
UPDATE July 2021:
The accepted solutions above have changed & improved much over time. The scope of my previous answer above was only to detect if the script was inserted in the document to load (and not whether the script has actually finished loading).
To detect if the script has already loaded, I use the following method (in general):
Create a common library function to dynamically load all scripts.
Before loading, it uses the isScriptLoaded(src) function above to check whether the script has already been added (say, by another module).
I use something like the following loadScript() function to load the script that uses callback functions to inform the calling modules if the script finished loading successfully.
I also use additional logic to retry when script loading fails (in case of temporary network issues).
Retry is done by removing the <script> tag from the body and adding it again.
If it still fails to load after configured number of retries, the <script> tag is removed from the body.
I have removed that logic from the following code for simplicity. It should be easy to add.
/**
* Mark/store the script as fully loaded in a global variable.
* #param src URL of the script
*/
function markScriptFullyLoaded(src) {
window.scriptLoadMap[src] = true;
}
/**
* Returns true if the script has been added to the page
* #param src URL of the script
*/
function isScriptAdded(src) {
return Boolean(document.querySelector('script[src="' + src + '"]'));
}
/**
* Returns true if the script has been fully loaded
* #param src URL of the script
*/
function isScriptFullyLoaded(src) {
return src in window.scriptLoadMap && window.scriptLoadMap[src];
}
/**
* Load a script.
* #param src URL of the script
* #param onLoadCallback Callback function when the script is fully loaded
* #param onLoadErrorCallback Callback function when the script fails to load
* #param retryCount How many times retry laoding the script? (Not implimented here. Logic goes into js.onerror function)
*/
function loadScript(src, onLoadCallback, onLoadErrorCallback, retryCount) {
if (!src) return;
// Check if the script is already loaded
if ( isScriptAdded(src) )
{
// If script already loaded successfully, trigger the callback function
if (isScriptFullyLoaded(src)) onLoadCallback();
console.warn("Script already loaded. Skipping: ", src);
return;
}
// Loading the script...
const js = document.createElement('script');
js.setAttribute("async", "");
js.src = src;
js.onload = () => {
markScriptFullyLoaded(src)
// Optional callback on script load
if (onLoadCallback) onLoadCallback();
};
js.onerror = () => {
// Remove the script node (to be able to try again later)
const js2 = document.querySelector('script[src="' + src +'"]');
js2.parentNode.removeChild(js2);
// Optional callback on script load failure
if (onLoadErrorCallback) onLoadErrorCallback();
};
document.head.appendChild(js);
}

This was very simple now that I realize how to do it, thanks to all the answers for leading me to the solution. I had to abandon $.getScript() in order to specify the source of the script...sometimes doing things manually is best.
Solution
//great suggestion #Jasper
var len = $('script[src*="Javascript/MyScript.js"]').length;
if (len === 0) {
alert('script not loaded');
loadScript('Javascript/MyScript.js');
if ($('script[src*="Javascript/MyScript.js"]').length === 0) {
alert('still not loaded');
}
else {
alert('loaded now');
}
}
else {
alert('script loaded');
}
function loadScript(scriptLocationAndName) {
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = scriptLocationAndName;
head.appendChild(script);
}

Create the script tag with a specific ID and then check if that ID exists?
Alternatively, loop through script tags checking for the script 'src' and make sure those are not already loaded with the same value as the one you want to avoid ?
Edit: following feedback that a code example would be useful:
(function(){
var desiredSource = 'https://sitename.com/js/script.js';
var scripts = document.getElementsByTagName('script');
var alreadyLoaded = false;
if(scripts.length){
for(var scriptIndex in scripts) {
if(!alreadyLoaded && desiredSource === scripts[scriptIndex].src) {
alreadyLoaded = true;
}
}
}
if(!alreadyLoaded){
// Run your code in this block?
}
})();
As mentioned in the comments (https://stackoverflow.com/users/1358777/alwin-kesler), this may be an alternative (not benchmarked):
(function(){
var desiredSource = 'https://sitename.com/js/script.js';
var scripts = document.getElementsByTagName('script');
var alreadyLoaded = false;
for(var scriptIndex in document.scripts) {
if(!alreadyLoaded && desiredSource === scripts[scriptIndex].src) {
alreadyLoaded = true;
}
}
if(!alreadyLoaded){
// Run your code in this block?
}
})();

Simply check if the global variable is available, if not check again. In order to prevent the maximum callstack being exceeded set a 100ms timeout on the check:
function check_script_loaded(glob_var) {
if(typeof(glob_var) !== 'undefined') {
// do your thing
} else {
setTimeout(function() {
check_script_loaded(glob_var)
}, 100)
}
}

Another way to check an external script is loaded or not, you can use data function of jquery and store a validation flag. Example as :
if(!$("body").data("google-map"))
{
console.log("no js");
$.getScript("https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false&callback=initilize",function(){
$("body").data("google-map",true);
},function(){
alert("error while loading script");
});
}
}
else
{
console.log("js already loaded");
}

I think it's better to use window.addEventListener('error') to capture the script load error and try to load it again.
It's useful when we load scripts from a CDN server. If we can't load script from the CDN, we can load it from our server.
window.addEventListener('error', function(e) {
if (e.target.nodeName === 'SCRIPT') {
var scriptTag = document.createElement('script');
scriptTag.src = e.target.src.replace('https://static.cdn.com/', '/our-server/static/');
document.head.appendChild(scriptTag);
}
}, true);

Merging several answers from above into an easy to use function
function GetScriptIfNotLoaded(scriptLocationAndName)
{
var len = $('script[src*="' + scriptLocationAndName +'"]').length;
//script already loaded!
if (len > 0)
return;
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = scriptLocationAndName;
head.appendChild(script);
}

My idead is to listen the error log if there is an error on script loading.
const checkSegmentBlocked = (e) => {
if (e.target.nodeName === 'SCRIPT' && e.target.src.includes('analytics.min.js')) {
window.isSegmentBlocked = true;
e.target.removeEventListener(e.type, checkSegmentBlocked);
}
};
window.addEventListener('error', checkSegmentBlocked, true);

Some answers on this page are wrong. They check for the existence of the <script> tag - but that is not enough. That tells you that the tag was inserted into the DOM, not that the script is finished loading.
I assume from the question that there are two parts: the code that inserts the script, and the code that checks whether the script has loaded.
The code that dynamically inserts the script:
let tag = document.createElement('script');
tag.type = 'text/javascript';
tag.id = 'foo';
tag.src = 'https://cdn.example.com/foo.min.js';
tag.onload = () => tag.setAttribute('data-loaded', true); // magic sauce
document.body.appendChild(tag);
Some other code, that checks whether the script has loaded:
let script = document.getElementById('foo');
let isLoaded = script && script.getAttribute('data-loaded') === 'true';
console.log(isLoaded); // true
If the both of those things (inserting and checking) are in the same code block, then you could simplify the above:
tag.onload = () => console.log('loaded');

I found a quick tip before you start diving into code that might save a bit of time. Check devtools on the webpage and click on the network tab. The js scripts are shown if they are loaded as a 200 response from the server.

Javascript file load fallback. Alternative to document.write()

You might be familiar with the good old Jquery load fallback:
<script>window.jQuery || document.write('<script src="https://example.com/jquery.js"></script>')</script>
But I read here and there: don’t use document.write, is bad for your health, it does not work on Chrome (It’s working for me, Chrome 78).
So I’m trying to replace it, but I’m not able to find a solution that will load synchronously the new js file, before DOM loaded is triggered.
And what ends happening with a DOM manipulation alternative is that the browser consideres the DOM is loaded and all $(document).ready() fail with “$ is not defined”.
function Jqfallback() {
var j = document.createElement('script');
j.src = 'https://example.com/jquery.js';
document.getElementsByTagName('head')[0].appendChild(j);
}
(window.jQuery || Jqfallback() );
No matter where I put this script, or the new JS file, which in this case ('head')[0] is already before all other JS which are in the body, it loads it “asyncronically”.
Is there another option or I continue rocking document.write() in late 2019?

It takes a bit of time to load and parse JQuery. So use a (small) timeout after appending the script.
This snippet wraps conditional loading in a immediately executed anonymous function:
(myScripting => {
if (!window.$) {
let j = document.createElement('script');
j.src = '//code.jquery.com/jquery-3.4.1.slim.min.js';
document.querySelector('head').appendChild(j);
setTimeout( myScripting, 200 );
} else {
myScripting();
}
})(JqIsLoadedSoMyScriptingCanStart);
// put your main scripting in here
function JqIsLoadedSoMyScriptingCanStart() {
// extra check
if (!window.$) {
alert("Sorry, JQuery is not loaded, can't continue");
return;
}
console.log("JQuery in place?");
console.log($("head script")[1]);
}
<script src="cantLoadThis"></script>

Place the code that uses jQuery in the onload() function.
var jQuery1 = document.createElement('script');
jQuery1.src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js";
jQuery1.onload = function () {
var $ = window.jQuery;
$.when(
$.getScript("https://someOtherScript.js"), //if you need
$.Deferred(function (deferred) {
$(deferred.resolve);
})
).done(function () {
console.log("all scripts loaded!!");
doNextTask(); //some other code which uses jQuery
});
};
Append jQuery to your document in onreadystatechange
document.onreadystatechange = function () {
if (document.readyState == "complete") {
// document is ready.
document.head.appendChild(jQuery1);
}
}

Intercept and alter a site's javascript using greasemonkey

Suppose there is a site that includes an external .js file in an html script tag like so:
<script src="somescript.js">
I want greasemonkey to intercept each of such scripts, and alter some of the values in them before they execute. For example, I want to change all occurrences of the value "400" to "300" within them, then continue to load the page as if the scripts used those values instead of the original ones. Currently I'm using the following code in greasemonkey:
function replaceTargetJavascript (scriptNode) {
var scriptSrc = scriptNode.textContent;
scriptSrc = scriptSrc.replace (
/'400'/,
"'300'"
);
addJS_Node (scriptSrc);
}
document.addEventListener("beforescriptexecute", function(e) {
checkForBadJavascripts ( [
[false, /'400'/, replaceTargetJavascript]
] );
}, true);
Which according to my sources is the right way to do it, but it is not working. Can anyone please help me figure this out?

Old question, but I needed to do this recently.
Here's how I did it using GreaseMonkey.
You add the beforescriptexecute listener, and wait for your target script to be loaded, checking the src tag to identify the correct script.
Then you stop that script from loading and get the script source yourself using GM_xmlhttpRequest.
Then you are free to modify the script as you please and insert it back into the DOM.
// ==UserScript==
// #name Test
// #namespace Test
// #description TEST
// #include http://the.website.com/*
// #version 1
// #grant GM_xmlhttpRequest
// #run-at document-start
// ==/UserScript==
function addScript(text) {
text = text.replace(/replaceThis();/g, "");
var newScript = document.createElement('script');
newScript.type = "text/javascript";
newScript.textContent = text;
var head = document.getElementsByTagName('head')[0];
head.appendChild(newScript);
}
window.addEventListener('beforescriptexecute', function(e) {
src = e.target.src;
if (src.search(/script_to_modify\.js/) != -1) {
e.preventDefault();
e.stopPropagation();
GM_xmlhttpRequest({
method: "GET",
url: e.target.src,
onload: function(response) {
addScript(response.responseText);
}
});
}
});

Override "Error Loading Page" for network failure in js file

I have JQuery Mobile-1.0.js file.
// Load a page into the DOM.
$.mobile.loadPage = function (url, options) {
// This function uses deferred notifications to let callers
// know when the page is done loading, or if an error has occurred.
var deferred = $.Deferred(),
// The default loadPage options with overrides specified by
// the caller.
settings = $.extend({}, $.mobile.loadPage.defaults, options),
// The DOM element for the page after it has been loaded.
page = null,
// If the reloadPage option is true, and the page is already
// in the DOM, dupCachedPage will be set to the page element
// so that it can be removed after the new version of the
// page is loaded off the network.
dupCachedPage = null,
// determine the current base url
findBaseWithDefault = function () {
var closestBase = ($.mobile.activePage && getClosestBaseUrl($.mobile.activePage));
return closestBase || documentBase.hrefNoHash;
},
// The absolute version of the URL passed into the function. This
// version of the URL may contain dialog/subpage params in it.
absUrl = path.makeUrlAbsolute(url, findBaseWithDefault());
// If the caller provided data, and we're using "get" request,
// append the data to the URL.
if (settings.data && settings.type === "get") {
absUrl = path.addSearchParams(absUrl, settings.data);
settings.data = undefined;
}
// If the caller is using a "post" request, reloadPage must be true
if (settings.data && settings.type === "post") {
settings.reloadPage = true;
}
// The absolute version of the URL minus any dialog/subpage params.
// In otherwords the real URL of the page to be loaded.
var fileUrl = path.getFilePath(absUrl),
// The version of the Url actually stored in the data-url attribute of
// the page. For embedded pages, it is just the id of the page. For pages
// within the same domain as the document base, it is the site relative
// path. For cross-domain pages (Phone Gap only) the entire absolute Url
// used to load the page.
dataUrl = path.convertUrlToDataUrl(absUrl);
// Make sure we have a pageContainer to work with.
settings.pageContainer = settings.pageContainer || $.mobile.pageContainer;
// Check to see if the page already exists in the DOM.
page = settings.pageContainer.children(":jqmData(url='" + dataUrl + "')");
// If we failed to find the page, check to see if the url is a
// reference to an embedded page. If so, it may have been dynamically
// injected by a developer, in which case it would be lacking a data-url
// attribute and in need of enhancement.
if (page.length === 0 && dataUrl && !path.isPath(dataUrl)) {
page = settings.pageContainer.children("#" + dataUrl)
.attr("data-" + $.mobile.ns + "url", dataUrl);
}
// If we failed to find a page in the DOM, check the URL to see if it
// refers to the first page in the application. If it isn't a reference
// to the first page and refers to non-existent embedded page, error out.
if (page.length === 0) {
if ($.mobile.firstPage && path.isFirstPageUrl(fileUrl)) {
// Check to make sure our cached-first-page is actually
// in the DOM. Some user deployed apps are pruning the first
// page from the DOM for various reasons, we check for this
// case here because we don't want a first-page with an id
// falling through to the non-existent embedded page error
// case. If the first-page is not in the DOM, then we let
// things fall through to the ajax loading code below so
// that it gets reloaded.
if ($.mobile.firstPage.parent().length) {
page = $($.mobile.firstPage);
}
} else if (path.isEmbeddedPage(fileUrl)) {
deferred.reject(absUrl, options);
return deferred.promise();
}
}
// Reset base to the default document base.
if (base) {
base.reset();
}
// If the page we are interested in is already in the DOM,
// and the caller did not indicate that we should force a
// reload of the file, we are done. Otherwise, track the
// existing page as a duplicated.
if (page.length) {
if (!settings.reloadPage) {
enhancePage(page, settings.role);
deferred.resolve(absUrl, options, page);
return deferred.promise();
}
dupCachedPage = page;
}
var mpc = settings.pageContainer,
pblEvent = new $.Event("pagebeforeload"),
triggerData = { url: url, absUrl: absUrl, dataUrl: dataUrl, deferred: deferred, options: settings };
// Let listeners know we're about to load a page.
mpc.trigger(pblEvent, triggerData);
// If the default behavior is prevented, stop here!
if (pblEvent.isDefaultPrevented()) {
return deferred.promise();
}
if (settings.showLoadMsg) {
// This configurable timeout allows cached pages a brief delay to load without showing a message
var loadMsgDelay = setTimeout(function () {
$.mobile.showPageLoadingMsg();
}, settings.loadMsgDelay),
// Shared logic for clearing timeout and removing message.
hideMsg = function () {
// Stop message show timer
clearTimeout(loadMsgDelay);
// Hide loading message
$.mobile.hidePageLoadingMsg();
};
}
if (!($.mobile.allowCrossDomainPages || path.isSameDomain(documentUrl, absUrl))) {
deferred.reject(absUrl, options);
} else {
// Load the new page.
$.ajax({
url: fileUrl,
type: settings.type,
data: settings.data,
dataType: "html",
success: function (html, textStatus, xhr) {
//pre-parse html to check for a data-url,
//use it as the new fileUrl, base path, etc
var all = $("<div></div>"),
//page title regexp
newPageTitle = html.match(/<title[^>]*>([^<]*)/) && RegExp.$1,
// TODO handle dialogs again
pageElemRegex = new RegExp("(<[^>]+\\bdata-" + $.mobile.ns + "role=[\"']?page[\"']?[^>]*>)"),
dataUrlRegex = new RegExp("\\bdata-" + $.mobile.ns + "url=[\"']?([^\"'>]*)[\"']?");
// data-url must be provided for the base tag so resource requests can be directed to the
// correct url. loading into a temprorary element makes these requests immediately
if (pageElemRegex.test(html)
&& RegExp.$1
&& dataUrlRegex.test(RegExp.$1)
&& RegExp.$1) {
url = fileUrl = path.getFilePath(RegExp.$1);
}
if (base) {
base.set(fileUrl);
}
//workaround to allow scripts to execute when included in page divs
all.get(0).innerHTML = html;
page = all.find(":jqmData(role='page'), :jqmData(role='dialog')").first();
//if page elem couldn't be found, create one and insert the body element's contents
if (!page.length) {
page = $("<div data-" + $.mobile.ns + "role='page'>" + html.split(/<\/?body[^>]*>/gmi)[1] + "</div>");
}
if (newPageTitle && !page.jqmData("title")) {
if (~newPageTitle.indexOf("&")) {
newPageTitle = $("<div>" + newPageTitle + "</div>").text();
}
page.jqmData("title", newPageTitle);
}
//rewrite src and href attrs to use a base url
if (!$.support.dynamicBaseTag) {
var newPath = path.get(fileUrl);
page.find("[src], link[href], a[rel='external'], :jqmData(ajax='false'), a[target]").each(function () {
var thisAttr = $(this).is('[href]') ? 'href' :
$(this).is('[src]') ? 'src' : 'action',
thisUrl = $(this).attr(thisAttr);
// XXX_jblas: We need to fix this so that it removes the document
// base URL, and then prepends with the new page URL.
//if full path exists and is same, chop it - helps IE out
thisUrl = thisUrl.replace(location.protocol + '//' + location.host + location.pathname, '');
if (!/^(\w+:|#|\/)/.test(thisUrl)) {
$(this).attr(thisAttr, newPath + thisUrl);
}
});
}
//append to page and enhance
// TODO taging a page with external to make sure that embedded pages aren't removed
// by the various page handling code is bad. Having page handling code in many
// places is bad. Solutions post 1.0
page
.attr("data-" + $.mobile.ns + "url", path.convertUrlToDataUrl(fileUrl))
.attr("data-" + $.mobile.ns + "external-page", true)
.appendTo(settings.pageContainer);
// wait for page creation to leverage options defined on widget
page.one('pagecreate', $.mobile._bindPageRemove);
enhancePage(page, settings.role);
// Enhancing the page may result in new dialogs/sub pages being inserted
// into the DOM. If the original absUrl refers to a sub-page, that is the
// real page we are interested in.
if (absUrl.indexOf("&" + $.mobile.subPageUrlKey) > -1) {
page = settings.pageContainer.children(":jqmData(url='" + dataUrl + "')");
}
//bind pageHide to removePage after it's hidden, if the page options specify to do so
// Remove loading message.
if (settings.showLoadMsg) {
hideMsg();
}
// Add the page reference and xhr to our triggerData.
triggerData.xhr = xhr;
triggerData.textStatus = textStatus;
triggerData.page = page;
// Let listeners know the page loaded successfully.
settings.pageContainer.trigger("pageload", triggerData);
deferred.resolve(absUrl, options, page, dupCachedPage);
},
error: function (xhr, textStatus, errorThrown) {
//set base back to current path
if (base) {
base.set(path.get());
}
// Add error info to our triggerData.
triggerData.xhr = xhr;
triggerData.textStatus = textStatus;
triggerData.errorThrown = errorThrown;
var plfEvent = new $.Event("pageloadfailed");
// Let listeners know the page load failed.
settings.pageContainer.trigger(plfEvent, triggerData);
// If the default behavior is prevented, stop here!
// Note that it is the responsibility of the listener/handler
// that called preventDefault(), to resolve/reject the
// deferred object within the triggerData.
if (plfEvent.isDefaultPrevented()) {
return;
}
// Remove loading message.
if (settings.showLoadMsg) {
// Remove loading message.
hideMsg();
//show error message
$("<div class='ui-loader ui-overlay-shadow ui-body-e ui-corner-all'><h1>" + $.mobile.pageLoadErrorMessage + "</h1></div>")
.css({ "display": "block", "opacity": 0.96, "top": $window.scrollTop() + 100 })
.appendTo(settings.pageContainer)
.delay(800)
.fadeOut(400, function () {
$(this).remove();
});
}
deferred.reject(absUrl, options);
}
});
}
return deferred.promise();
};
This is the code for showing an error message "Error Loading Page" for error in page. Here i want to show alert message for net connection failure as "Please check your net connection" instead of the below image.
Note: I dont want to change the pageloaderrormessage. want to stop to get the page error messages, instead of that i will enable my network error condition as in Show Network Error in android. If the user pressed "Ok" in alert dialog i'll navigate them into Reload.html.
Please tell me where i can check that condition and where i have to change the error message?

As both #shkschneider and #codemonkey have suggested you need to set this option on mobileinit
Example:
$(document).bind("mobileinit", function(){
$.mobile.pageLoadErrorMessage = "Please check your net connection";
});
Linking the jQM 1.0.1 docs:
http://jquerymobile.com/demos/1.0.1/docs/api/globalconfig.html
Here is a example:
http://jquerymobile.com/demos/1.0.1/docs/config/pageLoadErrorMessage.html ( click the "or Try this broken link" button )
Now if you have the ability to upgrade jQM to 1.1.1 you might try something like this:
//use theme swatch "b", a custom message, and no spinner
$.mobile.showPageLoadingMsg("b", "Please check your net connection", true);
// hide after delay
setTimeout( $.mobile.hidePageLoadingMsg, 1500 );
Docs:
http://jquerymobile.com/demos/1.1.1/docs/api/methods.html
UPDATE:
Another thought is to use a plugin to achieve something like you want, Does something like this work?
http://dev.jtsage.com/jQM-SimpleDialog/demos/bool.html

Simply use:
$(document).bind("mobileinit", function(){
$.mobile.pageLoadErrorMessage("Please check your netconnection");
});
http://jquerymobile.com/test/docs/api/globalconfig.html

Set the pageLoadErrorMessage as described here http://jquerymobile.com/demos/1.1.1/docs/api/globalconfig.html
EDIT
If you want to handle the behaviour in a custom way, set loadingMessage to false. This prevents the loading message from being displayed. You can bind to the pageloadfailed (described here http://jquerymobile.com/demos/1.1.1/docs/api/events.html) and add add your custom handling logic in the event handler.