In my JavaScript (using jQuery) there are a whole set of PHP variables to which I need access. While I've got it working by just producing the JavaScript file as a view, and then using renderPartial() to echo the JavaScript inside the main view.
However, this is obviously not very elegant, so I would like to know the 'Yii' way of doing it. I've been looking at the Assets Manager but that seems to be for static JavaScript files - you can't include PHP in there (unless I'm wrong).
Is there another way of doing it?
You may consider registerScript. In my opinion, it is better since there is a param named $position, which can help you control the process output of render().
There's nothing inherently wrong or inelegant with your approach, and yes assets are static content (JS, CSS, etc) -- unrelated to the issue.
Fundamentally you can only expose the value of a PHP variable in JS by writing it as part of PHP code. If you will only need this value in a limited scope then you could just write it as an inline constant (which is what e.g. some widgets do). If you need it to be available throughout your JS code the only option is to produce JS code like you do now.
It's not strictly necessary to make a new partial view for your PHP-to-JS variables, but it's also not a bad idea. If you are happy with it, by all means use it.
The one of approaches is to set global variable by a small script and redisterScript(), and then use this variable in real js
Setting your variables in a key=>value array and using CJSON::encode works really well. You can access all your variables via the object created by jQuery's parseJSON. For example:
$myVarList = array(
'nameOne'=>$valueFromAnotherVar,
'nameTwo'=>$object->coolValue,
'nameThree'=>$cat->hoursSleptToday()
);
Yii::app()->clientScript->registerScript("myVarList",
'myVarList = jQuery.parseJSON('.CJSON::encode($myVarList).');'
You can then access the values from the global var.
myVarList.nameOne || myVarList.nameTwo || myVarList.nameThree
Refer to Yii2 - Client Scripts Documentation, you can use registerJS function to pass variables to javascipt. For example:
/* #var $this yii\web\View */
$this->registerJs(
"var calenderEvents = ".Json::encode($calenderEvents).";",
yii\web\View::POS_HEAD,
'calender-events-script'
);
Try to do this that way:
$myVarList = array(
'nameOne'=>$valueFromAnotherVar,
'nameTwo'=>$object->coolValue,
'nameThree'=>$cat->hoursSleptToday()
);
$json = addslashes(CJSON::encode($myVarList));
Yii::app()->clientScript->registerScript("myVarList", 'myVarList =
jQuery.parseJSON("' . $json . '");');
Related
I have a form in JSP. I have to populate it based on the request object (from the servlet). How do I use Java Script for accessing request object attributes or if you can suggest me any other better way to populate form dynamically?
You need to realize that Java/JSP is merely a HTML/CSS/JS code producer. So all you need to do is to just let JSP print the Java variable as if it is a JavaScript variable and that the generated HTML/JS code output is syntactically valid.
Provided that the Java variable is available in the EL scope by ${foo}, here are several examples how to print it:
<script>var foo = '${foo}';</script>
<script>someFunction('${foo}');</script>
<div onclick="someFunction('${foo}')">...</div>
Imagine that the Java variable has the value "bar", then JSP will ultimately generate this HTML which you can verify by rightclick, View Source in the webbrowser:
<script>var foo = 'bar';</script>
<script>someFunction('bar');</script>
<div onclick="someFunction('bar')">...</div>
Do note that those singlequotes are thus mandatory in order to represent a string typed variable in JS. If you have used var foo = ${foo}; instead, then it would print var foo = bar;, which may end up in "bar is undefined" errors in when you attempt to access it further down in JS code (you can see JS errors in JS console of browser's web developer toolset which you can open by pressing F12 in Chrome/FireFox23+/IE9+). Also note that if the variable represents a number or a boolean, which doesn't need to be quoted, then it will just work fine.
If the variable happens to originate from user-controlled input, then keep in mind to take into account XSS attack holes and JS escaping. Near the bottom of our EL wiki page you can find an example how to create a custom EL function which escapes a Java variable for safe usage in JS.
If the variable is a bit more complex, e.g. a Java bean, or a list thereof, or a map, then you can use one of the many available JSON libraries to convert the Java object to a JSON string. Here's an example assuming Gson.
String someObjectAsJson = new Gson().toJson(someObject);
Note that this way you don't need to print it as a quoted string anymore.
<script>var foo = ${someObjectAsJson};</script>
See also:
Our JSP wiki page - see the chapter "JavaScript".
How to escape JavaScript in JSP?
Call Servlet and invoke Java code from JavaScript along with parameters
How to use Servlets and Ajax?
If you're pre-populating the form fields based on parameters in the HTTP request, then why not simply do this on the server side in your JSP... rather than on the client side with JavaScript? In the JSP it would look vaguely like this:
<input type="text" name="myFormField1" value="<%= request.getParameter("value1"); %>"/>
On the client side, JavaScript doesn't really have the concept of a "request object". You pretty much have to parse the query string yourself manually to get at the CGI parameters. I suspect that isn't what you're actually wanting to do.
Passing JSON from JSP to Javascript.
I came here looking for this, #BalusC's answer helped to an extent but didn't solve the problem to the core. After digging deep into <script> tag, I came across this solution.
<script id="jsonData" type="application/json">${jsonFromJava}</script>
and in the JS:
var fetchedJson = JSON.parse(document.getElementById('jsonData').textContent);
In JSP file:
<head>
...
<%# page import="com.common.Constants" %>
...
</head>
<script type="text/javascript">
var constant = "<%=Constants.CONSTANT%>"
</script>
This constant variable will be then available to .js files that are declared after the above code.
Constants.java is a java file containing a static constant named CONSTANT.
The scenario that I had was, I needed one constant from a property file, so instead of constructing a property file for javascript, I did this.
In JSP page :
<c:set var="list_size" value="${list1.size() }"></c:set>
Access this value in Javascipt page using :
var list_size = parseInt($('#list_size').val());
I added javascript page in my project externally.
I have a form in JSP. I have to populate it based on the request object (from the servlet). How do I use Java Script for accessing request object attributes or if you can suggest me any other better way to populate form dynamically?
You need to realize that Java/JSP is merely a HTML/CSS/JS code producer. So all you need to do is to just let JSP print the Java variable as if it is a JavaScript variable and that the generated HTML/JS code output is syntactically valid.
Provided that the Java variable is available in the EL scope by ${foo}, here are several examples how to print it:
<script>var foo = '${foo}';</script>
<script>someFunction('${foo}');</script>
<div onclick="someFunction('${foo}')">...</div>
Imagine that the Java variable has the value "bar", then JSP will ultimately generate this HTML which you can verify by rightclick, View Source in the webbrowser:
<script>var foo = 'bar';</script>
<script>someFunction('bar');</script>
<div onclick="someFunction('bar')">...</div>
Do note that those singlequotes are thus mandatory in order to represent a string typed variable in JS. If you have used var foo = ${foo}; instead, then it would print var foo = bar;, which may end up in "bar is undefined" errors in when you attempt to access it further down in JS code (you can see JS errors in JS console of browser's web developer toolset which you can open by pressing F12 in Chrome/FireFox23+/IE9+). Also note that if the variable represents a number or a boolean, which doesn't need to be quoted, then it will just work fine.
If the variable happens to originate from user-controlled input, then keep in mind to take into account XSS attack holes and JS escaping. Near the bottom of our EL wiki page you can find an example how to create a custom EL function which escapes a Java variable for safe usage in JS.
If the variable is a bit more complex, e.g. a Java bean, or a list thereof, or a map, then you can use one of the many available JSON libraries to convert the Java object to a JSON string. Here's an example assuming Gson.
String someObjectAsJson = new Gson().toJson(someObject);
Note that this way you don't need to print it as a quoted string anymore.
<script>var foo = ${someObjectAsJson};</script>
See also:
Our JSP wiki page - see the chapter "JavaScript".
How to escape JavaScript in JSP?
Call Servlet and invoke Java code from JavaScript along with parameters
How to use Servlets and Ajax?
If you're pre-populating the form fields based on parameters in the HTTP request, then why not simply do this on the server side in your JSP... rather than on the client side with JavaScript? In the JSP it would look vaguely like this:
<input type="text" name="myFormField1" value="<%= request.getParameter("value1"); %>"/>
On the client side, JavaScript doesn't really have the concept of a "request object". You pretty much have to parse the query string yourself manually to get at the CGI parameters. I suspect that isn't what you're actually wanting to do.
Passing JSON from JSP to Javascript.
I came here looking for this, #BalusC's answer helped to an extent but didn't solve the problem to the core. After digging deep into <script> tag, I came across this solution.
<script id="jsonData" type="application/json">${jsonFromJava}</script>
and in the JS:
var fetchedJson = JSON.parse(document.getElementById('jsonData').textContent);
In JSP file:
<head>
...
<%# page import="com.common.Constants" %>
...
</head>
<script type="text/javascript">
var constant = "<%=Constants.CONSTANT%>"
</script>
This constant variable will be then available to .js files that are declared after the above code.
Constants.java is a java file containing a static constant named CONSTANT.
The scenario that I had was, I needed one constant from a property file, so instead of constructing a property file for javascript, I did this.
In JSP page :
<c:set var="list_size" value="${list1.size() }"></c:set>
Access this value in Javascipt page using :
var list_size = parseInt($('#list_size').val());
I added javascript page in my project externally.
I have a form in JSP. I have to populate it based on the request object (from the servlet). How do I use Java Script for accessing request object attributes or if you can suggest me any other better way to populate form dynamically?
You need to realize that Java/JSP is merely a HTML/CSS/JS code producer. So all you need to do is to just let JSP print the Java variable as if it is a JavaScript variable and that the generated HTML/JS code output is syntactically valid.
Provided that the Java variable is available in the EL scope by ${foo}, here are several examples how to print it:
<script>var foo = '${foo}';</script>
<script>someFunction('${foo}');</script>
<div onclick="someFunction('${foo}')">...</div>
Imagine that the Java variable has the value "bar", then JSP will ultimately generate this HTML which you can verify by rightclick, View Source in the webbrowser:
<script>var foo = 'bar';</script>
<script>someFunction('bar');</script>
<div onclick="someFunction('bar')">...</div>
Do note that those singlequotes are thus mandatory in order to represent a string typed variable in JS. If you have used var foo = ${foo}; instead, then it would print var foo = bar;, which may end up in "bar is undefined" errors in when you attempt to access it further down in JS code (you can see JS errors in JS console of browser's web developer toolset which you can open by pressing F12 in Chrome/FireFox23+/IE9+). Also note that if the variable represents a number or a boolean, which doesn't need to be quoted, then it will just work fine.
If the variable happens to originate from user-controlled input, then keep in mind to take into account XSS attack holes and JS escaping. Near the bottom of our EL wiki page you can find an example how to create a custom EL function which escapes a Java variable for safe usage in JS.
If the variable is a bit more complex, e.g. a Java bean, or a list thereof, or a map, then you can use one of the many available JSON libraries to convert the Java object to a JSON string. Here's an example assuming Gson.
String someObjectAsJson = new Gson().toJson(someObject);
Note that this way you don't need to print it as a quoted string anymore.
<script>var foo = ${someObjectAsJson};</script>
See also:
Our JSP wiki page - see the chapter "JavaScript".
How to escape JavaScript in JSP?
Call Servlet and invoke Java code from JavaScript along with parameters
How to use Servlets and Ajax?
If you're pre-populating the form fields based on parameters in the HTTP request, then why not simply do this on the server side in your JSP... rather than on the client side with JavaScript? In the JSP it would look vaguely like this:
<input type="text" name="myFormField1" value="<%= request.getParameter("value1"); %>"/>
On the client side, JavaScript doesn't really have the concept of a "request object". You pretty much have to parse the query string yourself manually to get at the CGI parameters. I suspect that isn't what you're actually wanting to do.
Passing JSON from JSP to Javascript.
I came here looking for this, #BalusC's answer helped to an extent but didn't solve the problem to the core. After digging deep into <script> tag, I came across this solution.
<script id="jsonData" type="application/json">${jsonFromJava}</script>
and in the JS:
var fetchedJson = JSON.parse(document.getElementById('jsonData').textContent);
In JSP file:
<head>
...
<%# page import="com.common.Constants" %>
...
</head>
<script type="text/javascript">
var constant = "<%=Constants.CONSTANT%>"
</script>
This constant variable will be then available to .js files that are declared after the above code.
Constants.java is a java file containing a static constant named CONSTANT.
The scenario that I had was, I needed one constant from a property file, so instead of constructing a property file for javascript, I did this.
In JSP page :
<c:set var="list_size" value="${list1.size() }"></c:set>
Access this value in Javascipt page using :
var list_size = parseInt($('#list_size').val());
I added javascript page in my project externally.
Yo!
I have an arbitrary javascript file, let's call it localScript, and just say it looks something like this:
<script id="myScript" type="text/javascript">
function () {
var blue = 'blue';
var person = {
firstName:"John",
lastName:"Doe",
age:50,
eyeColor:"brown"
};
var bluePerson = function () {
person[color] = blue;
};
}
</script>
I want to be able to use another externalScript to dynamically change the contents of this localScript. For this simple example, let's just say I want to update some of the values in localScript, like—maybe change age of the person object to 75. (Obviously, there's very simple ways to do this, but for my use case it's imperative that I use another externalScript to generate the contents of this localScript).
It would be easy if there was something like .innerHtml which I could use in the externalScript which would allow me to select an element and then replace the 'innerHtml' contents. The localScript, though, obviously isn't composed of elements.
As far as I know, when using a script to modify another script, there aren't any 'easy' ways to reference variables/objects/items in the script.
Things I've considered are indexOf(), search(), and match(), which I could use in externalScript to find strings inside localScript and then replace the values. I feel though as these could be performance no-no's, especially if the script grows.
Are there any easy ways to do this—with an emphasis on performance? I feel like there must be some easy way to reference one of the items in the script, though, I suppose a script is all one large string.. and maybe there is no simple way.
BTW—I'm using AngularJS, if there are any built in methods—though I think this is mostly just a javascript thing.
Thanks a bunch!
It looks like a bad idea, but... well, if it is imperative...
It makes no sense to change a script in a <script> tag - if it is in DOM, it has already executed (and no longer matters). Thus, to change the script before it has a chance to execute, you need to load it using AJAX, change the text, then eval it.
You can easily change the variables. Refer following steps
Include external script just below the script you have written.
Access the variables in the external script as if they are locally declared.
The variables you have created in above script are available in global scope and hence should be accessible from everywhere.
Note: This answer was added before the function clause was added.
In PHP, I used to do things like this :
<?php
use Vendor/Namespace/Bundle;
$bundle = new Bundle();
What interests me here is that, following the PSR-4 convention (or any other convention), we could automatically require a PHP file and use its content. Is there any ways to do this in Javascript, or how to do not use some ugly require('../../../../../../../mymodule.js'); ?
Set the $NODE_PATH variable to whichever location you want require to look into by default.
http://nodejs.org/api/modules.html#modules_loading_from_the_global_folders
For e.g. setting it to /user/project/lib; you can do a require('mymodule.js') from, say /user/project/test/test.js, it'll work.