Include a JavaScript library in a JSP file - javascript

I'm trying to use JavaScript functions from the a JavaScript library in my JSP file to display the result on a web-browser page, but it seems like the inclusion didn't work.
I actually put the .js file corresponding to the library in the WEB-INF folder and added the following line in the JSP file to include it in it :
<script type="text/javascript" src="./jsgl.min.js"></script>
I successfully managed to use the library in a simple HTML file, that's why I don't understand why this doesn't work.
EDIT :

TLDR
Put the JS file in a folder under web content (but not WEB-INF) like [WebContent]/js/jsgl.min.js, and use the following in the JSP:
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jsgl.min.js"></script>
Explanation
JSP files are compiled by the server, then processed to send data (typically HTML) back to the web browser. A <script> tag is a HTML tag that gets interpreted by the browser, not by the servlet container. So the browser sees that in the HTML then makes a new request to the server for the JavaScript file in the src attribute.
The src attribute is relative to the URL that the browser asked for, not to the path of the JSP on the server.
So as an example, let's say:
The browser asks for a page at http://example.com/SomeWebApp/some-resource
The servlet container internally forwards the request to a JSP at /WEB-INF/jsp/somepage.jsp
The response sent to the browser contains the script tag <script type="text/javascript" src="./jsgl.min.js"></script> (as in your question)
The browser sees the URL ./jsgl.min.js and resolves it relative to the URL it has asked the server for (which in this case was http://example.com/SomeWebApp/some-resource - note there is no trailing '/') so the browser will request the JS file from http://example.com/SomeWebApp/jsgl.min.js*. This is because the relative URL in the script tag's src attribute starts with a '.'.
Another answer suggested putting the JS file in a 'js' folder and changing the script tag to <script type="text/javascript" src="/js/jsgl.min.js"></script>. Using the same original page URL as in the example above, the browser would translate this src URL to http://example.com/js/jsgl.min.js. Note that this is missing the "/SomeWebApp" context path.
The best solution therefore is indeed to put the JS file in a static folder like /js/jsgl.min.js, but to use the following in the JSP script tag:
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jsgl.min.js"></script>
The JSP will translate the ${pageContext.request.contextPath} bit into the current context path, making the code portable (if you redeploy the webapp with a different context path, it will still work). So the HTML response received by the browser will be (again, sticking with our example above):
<script type="text/javascript" src="/SomeWebApp/js/jsgl.min.js"></script>
The browser will now resolve that relative URL to the correct target.
__
*If the original URL had a trailing slash = i.e., was http://example.com/SomeWebApp/some-resource/, the JS URL would be http://example.com/SomeWebApp/some-resource/jsgl.min.js

Static resources should be put outside the WEB-INF folder (as you would typically not allow web access to its content).
You could put the file under webapp/js/, then change your script import to:
<script type="text/javascript" src="/js/jsgl.min.js"></script>
In addition to being good practice, this is good as it is not relative to the location of the JSP file.

Files in WEB-INF are inaccessible.
You may put them under webapp and try accessing as mentioned above.

Related

Thymeleaf: how to pass main.js to require.js via data-main

We have a project where we want to use require.js along with our uncompressed main app.js in developer environments, so we have tried this script declaration in our main Thymeleaf template html:
<script
th:if="${#applicationProperties.getStage() == 'dev'}"
th:src="#{'/js/shared/lib/amd/require.min.js'}"
data-main="#{'/js/app.js'}">
</script>
Watching the network traffic in the browser shows, that loading the require.min.js works, so Thymeleaf prepends the context in the th:src.
Also the app.js obviously is passed to require since you can see that the browser is trying to load whatever you pass to require via data-main.
However, using #{} to prepend the context to "/js/app.js" results in something like http://localhost:7000/myapp/#%7B'/js/app.js'%7D.js. So I assume Thymeleaf is not processing the value of the data-main tag.
Using data:main from Thymeleaf does not work at all.
If we hard code the context path, then everything is fine:
data-main="/myapp/js/app.js">
So, how can we prepend the context path to the script location?
The solution is:
<script type="text/javascript"
th:if="${#applicationProperties.getStage() == 'dev'}"
th:src="#{'/js/shared/lib/amd/require.min.js'}"
th:attr="data-main=#{/js/app.js}">
</script>
Note, that there are no apostrophes in the value of th:attr!

Where is external js file in html stored? Can I

Sorry, I don't have a good understanding of the web, but:
When you load in an external script file into an html document, where does it hold or cache that file? It doesn't put it in the index.html file.
<html>
<head>
<script src="name_of_file"></script>
</head>
.....
I ask because I'm working with node.js, and I'm wondering if I list an external script file under my index.html page, I can send the javascript file to the client.
the browser will recognize the "src"="http://xxx/xx.js" of your script tag,and check if the resources(identified with URI:"http://xxx/xx.js") has cached in browser local cache dir(every browser has its own dir)
if the file exist and cache is not expired,the browser will directly load this file,otherwise browser will download the script file,and execute them when download finish.
This question has no good answer. A JavaScript program can be located anywhere on a server, It's just linked to with <script src=SCRIPT></script> Where SCRIPT is the relative or absolute path to the .js file. Check out This site for more info.
It's wherever the file is being served from. With what you've given and default setup, the file will be in the same directory as your index.html file

Using external JavaScript files in a WinForms/WPF WebBrowser control

I found a cool feature on a website, implemented in JavaScript, I'd like to use it as is in my desktop application (for personal use).
During my experiments I managed to generate custom HTML on the fly, feed it to the browser using webBrowser1.DocumentText = [my generated HTML]
I've managed to put some inline JavaScript into the HTML, and hook it up via a ScriptManager so that I can call the JavaScript from my C# code, pass a value to it, and get a return value.
But the feature I'm trying to use is a bit more complicated: it's no less than 10 JavaScript files. 2 of them are referenced directly in the web page the usual way <script src="/js/script1.js" type="text/javascript"></script>
The other 8 are loaded in one of the scripts:
var elem = document.createElement("script");
elem.type = "text/javascript";
elem.src = "/js/" + filename;
document.body.appendChild(elem);
These 8 files are in fact data files, even though the data is represented in JavaScript. They're pretty large, over 1MB each. Stuffing it all into the HTML file seems quite stupid. Also, the script that loads the data creates a "file map" and further refers to the data based on which file it's in:
var fileMap = [
[/[\u0020-\u00ff]/, 'file1.js'],
[/[\u3000-\u30ff]/, 'file2.js'],
[/[\u4e00-\u5dff]/, 'file3.js'],
...
I don't want to resort to modifying the JavaScript, because it's not exactly my strong point. So the browser needs to "see" the js files in order to be able to use them. I thought of creating the file structure locally, and navigating the browser there. But I don't want any loose files in my solution. I'd like to have everything embedded if possible. And I doubt I can get the browser to navigate to an embedded resource, and see other embedded resources as files. Any idea how I could get around this?
EDIT:
I've tried to do it with local files. No luck. I get the HTML to load properly, but when I try to invoke a JavaScript call, nothing happens. I tried pointing the browser to those js files, to make sure they're there. They are. I tried an element with src attribute pointing to an image in the same subfolder as the script files. It gets rendered. It's as if external js files refuse to load.
I had a similar need as your scenario and I addressed it using two key points embedded in two other Stack Overflow answers. As noted by SLaks' answer here the first key is using the syntax file:/// as the prefix for an absolute path to external files. The second is using .Replace("\\", "/") for an absolute file path as listed in Adam Plocher's answer and one of his follow-up comments here.
In short, the final output for each external file in an HTML page will look something like:
<link href="file:///c:/users/david/myApp/styles/site.css" rel="stylesheet" type="text/css">
or
<script src="file:///c:/users/david/myApp/scripts/JavaScript1.js"></script>
Using the format in the samples above in my HTML file resulted in the WebBrowser control loading external CSS, image or script files.
The details and solving the scenario in the question
In the womd's answer in the first referenced SO answer above he used the method System.IO.File.ReadAllText() to load script files and embedded the text of the script files into the <head> tag. As you indicated in your question loading script files directly into the HTML page is not what you're looking to do.
The solution below involves using the same System.IO.File.ReadAllText() method but loads the text of the HTML page instead. The premise works similar to the Razor View Engine in ASP.NET.
The main idea in the solution below involves adding a temporary string in an HTML page that will be loaded into the WebBrowser control and then replacing this temporary string in a C# method in my app just before the HTML page is set to be loaded into the WebBrowser control.
Here are the basic steps to my solution:
Add a temporary string for each external reference in the HTML file.
Declare a variable for the absolute path in a script tag within the HTML file. This step is not necessary unless you're going to use the absolute path elsewhere within your JavaScript code. Your scenario involves delay loading external script files via JavaScript code so this step was necessary.
Modify the src property in the JavaScript code that delay loads the other script files with the absolute path variable.
Add a method in your app to loads the HTML page file as a text string and then replaces all temporary string instances with an absolute path containing the prefix 'file:///'. The absolute path should have forward slashes.
Set the 'DocumentText' property on the WebBrowser control to the updated HTML.
Set the 'Copy to Output Directory' of each external file in your project to 'Copy always' or 'Copy if newer'. This step may not be necessary if you have a fixed location to your external files and that location is not within the build or publish directory used by Visual Studio.
The following are the details for each step. I added a lot of detail that you can skip. I was verbose to reduce any confusion since the steps make changes to several places in the project.
1. Using a temporary string
I used the string "/ReplaceWithAbsolutePath/" but you can use any distinct text. Each reference to an external file in the HTML page looks like:
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title></title>
<link href="/ReplaceWithAbsolutePath/styles/site.css" rel="stylesheet" type="text/css">
<script type="text/javascript">
var absolutePath = "/ReplaceWithAbsolutePath/";
</script>
</head>
<body>
<p>My web page</p>
<script src="/ReplaceWithAbsolutePath/scripts/JavaScript1.js"></script>
</body>
</html>
2. Declare absolute path variable
Note in the above HTML page I listed a <script> tag with the declared variable 'absolutePath' set to the temporary string. (In the HTML page above the variable is added a global variable and that is not necessarily best practice. You can declare the variable within a namespace instead of declaring it in the global namespace.)
3. Modify the delay load script to include absolute path variable
Add the 'absolutePath' variable to your JavaScript file that delay loads other JavaScript files containing your data.
elem.src = absolutePath + "/js/" + filename;
4. C# method to replace all temporary string instances
Within your project add the following line to your form load event handler or place this line somewhere in your initialization of the WebBrowser control.
webBrowser1.DocumentText = GetUpdatedHtmlWithAbsolutePaths("/ReplaceWithAbsolutePath/", "HTMLPage1.html");
Add the following method to your code. Update the call to the method in the line above with the name of the class instance where the following method is placed.
// The result of this method will look like the following example:
// <script src="file:///c:/users/david/documents/myApp/scripts/JavaScript1.js"></script>
public string GetUpdatedHtmlWithAbsolutePaths(string tempPathString, string htmlFilename)
{
// Get the directory as the application
// stackoverflow.com/questions/674857/should-i-use-appdomain-currentdomain-basedirectory-or-system-environment-current
// Note that the 'BaseDirectory' property will return a string with trailing backslashes ('\\')
string appDirectory = AppDomain.CurrentDomain.BaseDirectory;
// Replace '//' with '/' in the appDirectory string
appDirectory = appDirectory.Replace("\\", "/");
// Read all of the HTML text from the HTML page file
string html = System.IO.File.ReadAllText(appDirectory + #"\" + htmlFilename);
// Replace all '/ReplaceWithAbsolutePath/' strings within the HTML text with
// the absolute path on the local machine
html = html.Replace(tempPathString, "file:///" + appDirectory);
return html;
}
5. Set the DocumentText property of the WebBrowser control
I added the initialization of the WebBrowser control in the form load event handler but you can, of course, add the line that sets the DocumentText property wherever you initialize your WebBrowser control.
private void Form1_Load(object sender, EventArgs e)
{
// Set the document text of the web browser control with the updated HTML
webBrowser1.DocumentText = GetUpdatedHtmlWithAbsolutePaths("HTMLPage1.html");
}
6. Set the 'Copy to Output Directory' of each external file
Take a look at the answer posted by Matthew Watson in this Stack Overflow question if you want your external files included in your solution/project file structure.
You can add files to your project and select their properties: "Build
Action" as "Content" and "Copy to output directory" as "Copy Always"
or Copy if Newer (the latter is preferable because otherwise the
project rebuilds fully every time you build it).
Then those files will be copied to your output folder.
This is better than using a post build step because Visual Studio will
know that the files are part of the project. (That affects things like
ClickOnce applications which need to know what files to add to the
clickonce data.)
In short, add the external file to your project. You can add the external to any subfolder in your project. (In Visual Studio 2013 or 2015 -- I don't have VS2012) Right-click on the external file in the Solution Explorer and select Properties from the context menu. The Properties pane will be displayed. In the Properties pane change the setting for 'Copy to Output Directory' to 'Copy always' or 'Copy if newer'.
Use View Source to verify absolute path strings
Run your project and it should load your external files in the WebBrowser control. Assuming you have not set the property wbChartContainer.IsWebBrowserContextMenuEnabled = false; in code or in the Properties pane for WebBrowser control you can right-click on the WebBrowser control when your form is running. Click 'View Source' from the context menu and check the paths to your external resources in the View Source window.

javascript file not loading

Trying to import my js file from my page.
My page is in webcontent/mydomain/templates/page.xhtml
My js is in webcontent/mydomain/test/scripts
In page.xhtml
<script type="text/javascript" src="../test/scripts/test.js"></script>
But still the script is not getting picked.
Can anyone tell how I need to give the path in src.
Try this:
<script src="/test/scripts/test.js"></script>
Provided that webcontent is the root of public web content and thus /mydomain is also a public folder and thus your JavaScript is standalone available by http://localhost:8080/context/mydomain/test/scripts/test.js, assuming a domain of http://localhost:8080 and a context path of /context, then the following should do:
<script src="#{request.contextPath}/mydomain/test/scripts/test.js"></script>
This will generate a domain-relative URL with a dynamically inlined context path, which is much more robust than fiddling with ../ which would make the URI relative to the current request URI (as you see in browser's address bar) and not to the physical location of the template file as many starters incorrectly assume.

Android webview load local javascript

I am trying to load a javascript file stored on the device via html file which is loaded via a webview but never seems to load. I have tried using direct url's like you normally would in html and have also tried:
<script type="text/javascript" src="file:///android_asset/www/js/jsfile.js"/>
JavaScript is enabled on the webview settings too and works fine if I have it on a server.
Thanks if anyone can help.
Hi actually I thing you should call directly the js file because you are calling it from the browser which considers the asset folder being its root folder. You should use the "file:///" prefix when calling from java code. Try something like this:
<script type="text/javascript" src="www/js/jsfile.js"/>
You can use loadDataWithBaseURL.
Put all your javascript under an assets folder and give js file path relative to the assets directory in your script tag (in the html). Don't put a slash in the beginning of src.
Read the html into a string (htmlStr) and then load it in the webview as mentioned below.
webView.loadDataWithBaseURL("file:///android_asset/", htmlStr, "text/html", "UTF-8", null);
It has worked for me.

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