Issue in JavaScript retrieve information - javascript

Premise: I've started to study javascript and the DOM and I have this HTML fragment:
<body>
<div id="Area_T10" class="abAdArea">
<script src="http://ad.dc2.adtech.de/addyn/3.0/831/***1644116***/0/744/ADTECH;" language="javascript1.1" type="text/javascript"></script>
<script>
** -- My script var n = **
</script>
</div>
</body>
I want to retrieve the number "16644116" from the div but I cannot figure out how to do it.
Can you help?
Best Regards.
Domenico

I am assuming you want to extract the number from the script source URL.
First step, get the script source value:
var src = document.getElementsByTagName('script')[0].src;
Then, if you're familiar with regular expressions, you should be able to create a pattern to extract that value.

Extract the URL from the attribute using whichever DOM manipulation technique you prefer (perhaps a library)
Use a regular expression to extract the desired portion of the URL

Related

parse <script> tag with js/jQuery

I have a HTML page where a user is able to edit a HTML resource (using ACE Editor). Within this HTML source, there is a <script>-tag, which does some pretty basic stuff.
Is there any elegant solution to parse the script tag in order to (e.g.) evaluate the variables used within the script tag? For "normal" tags I use parseHTML() to have the html as a jQuery object.
From this example, I would like to retrieve the value of $myVal (which is "f00") and write it to #myLabel:
<textarea id="myScript" rows="5" readonly>
<script>
$myVal = "f00";
</script>
</textarea>
<label id="myLabel">Hello</label>
$(function(){
$scriptVar = $('#myScript').text;
// parse the $scriptVar
// retrieve the value of, $myVal, write it to #myLabel
//$myParsedValue = ???
//$('#myLabel').text('bar!');
});
And here is the fiddle: https://jsfiddle.net/stepdown/jqcut0sn/
Is this possible at all? I don't really care about vanilla js, jQuery, regex or maybe even an external library for that purpose.
Thanks to #JeremyThille, who pointed me to the right direction. I found out, what I want to achieve is possible through jQuerys $.globalEval() - see the official documentation.
Basically what globalEval() does: it runs the script which is written in the <textarea> and makes the variables / functions globally accessible.
IMPORTANT: this implies, that syntax errors (etc) by the user will break the evaluation, and sequential functionality could be flawed. Also, the new variables are GLOBAL, so basically a user could rewrite scripts on the hosting page. (In my case both problems are of minor importance, since this is an internal application for trained users - they also have syntax highlighting through the amazing ACE editor. But I wanted to make sure to point it out. Also, there are several articles regarding the risks/ouch-moments when using eval()...)
I updated the fiddle to achieve what I wanted: https://jsfiddle.net/stepdown/Lxz7q6uv/
HTML:
<textarea id="myScript" rows="5" readonly>
$myVal = "f00";
</textarea>
<hr />
<label id="myLabel">Hello</label>
Script:
$(function(){
var myScriptContent = $('#myScript').text();
$.globalEval(myScriptContent);
console.log($myVal);
$('#myLabel').text($myVal);
});

Extract all classes from body element of AJAX-ed page and replace current page's body classes

I am in the process of AJAX-ing a WordPress theme with a persistent music player. Wordpress uses dynamic classes on the <body> tag. The basic structure is as follows:
<html>
<head>
</head>
<body class="unique-class-1 unique-class-2 unique-class-3">
<div id="site-container">
<nav class="nav-primary">
Other Page 01
Other Page 02
</nav>
<div class="site-inner">
<p>Site Content Here</p>
</div>
</div>
<div id="music-player"></div>
</body>
</html>
I am currently successfully loading the content of /other-page-01/, /other-page-02/, etc, using load('/other-page-01/ #site-container'). However, I need to extract all <body> classes from the AJAX loaded page and replace the current page's <body> classes with them dynamically.
Note: Replacing the entire <body> element is not an option due to the persistent <div id="music-player">. I've tried jQuery.get(), but couldn't get it to work.
How do I extract the <body> classes from the AJAX requested page and replace the current page's <body> classes with them?
I am not very familiar with jQuery or Javascript, so the exact code would be extremely helpful. Any help is greatly appreciated.
Thanks,
Aaron
My typical solution would have been to tell you to throw the AJAX code in to a jQuery object and then read it out like normal:
$(ajaxResult).attr('class');
Interestingly though, it appears you can't do this with a <body> element.
I'd say the easiest solution (if you have control over the resulting HTML) is to just use some good ol' regex:
var matches = ajaxResult.match(/<body.*class=["']([^"']*)["'].*>/),
classes = matches && matches[1];
I say "if you have control over the resulting HTML", because this relies on the HTML being reasonably well formed.
The other method would involve parsing it as a DOMDocument and then extracting what you need, but this would take a lot more and is usually overkill in simple cases like this.
Convert the body within your returned html to a div with a specific ID, then target that id to get the classes of the body (which is now a div.)
modifiedAjaxResult = ajaxResult.replace(/<body/i,'<div id="re_body"')
.replace(/<\/body/i,'</div');
$(modifiedAjaxResult).filter("#re_body").attr("class");
Of course, if the body has an id, this will conflict with it, so an arbitrary data attribute might be less likely to break.
modifiedAjaxResult = ajaxResult.replace(/<body/i,'<div data-re-id="re_body"')
.replace(/<\/body/i,'</div');
$(modifiedAjaxResult).filter("[data-re-id=re_body]").attr("class");
http://jsfiddle.net/N68St/
Of course, to use this method, you'll have to switch to using $.get instead.
$.get("/other-page-01/",function(ajaxResult){
var modifiedAjaxResult = ajaxResult.replace(/<body/i,'<div data-re-id="re_body"')
.replace(/<\/body/i,'</div');
alert($(modifiedAjaxResult).filter("[data-re-id=re_body]").attr("class"));
// the following line replicates what `.load` was doing.
$(someElement).append( $("<div>").html(ajaxResult).find("#site-container") );
});

Newbie to jQuery and get function

I am completely new to jQuery. I can't find any good documentation on the get function and was wondering if I could get some help.
I have an HTML page called me.html with just a single div called me. I want to use the following page to get the contents within the div. Even a google in the right direction would help. Thanks so much
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript" src="data.js"></script>
</head>
<body>
<form id="form" runat="server">
<div>
<div id="me">
</div>
</div>
</form>
</body>
</html>
you don't need to use get(). This simple script should do it
<script>
var contentsOfMe = $('#me').html();
</script>
get is used for loading data from an url. You seem to be wanting to get the contents of a div
as in $("#me").text()
What about using the great documentation provided at http://api.jquery.com/jQuery.get/
EDIT. If you want to just get the text, use var myText=$('#me').html();, and if the html, use var myHtml=$('#me').html();
You will find the documentation for the function get here : http://api.jquery.com/jQuery.get/
But get is to perform an ajax request get on your server so I don't think that's what you need.
In jquery, most of the time you will "select" an element using jquery selector : $("#id")
This will select $(), this will say you are selecting an element using his id $("#name_of_the_id").
Then, you will have an object which will represent the selected element.
If you want to get all the html inside this element do :
function getHtmlFromElementId(id)
{
var element = $("#" + id);
var html = element.html();
return html;
}
Printing the return of this function will print all html code inside the element selected.
If you are seaching for a good tutorial on jquery, the w3schools' one is really good:
http://www.w3schools.com/jquery/jquery_examples.asp

Razor syntax in JavaScript code block

I want to know if it is a good practice to use razor in JavaScript code. For example:
<script type="text/javascript">
var variable = #some.Id
</script>
Or it's better to create hidden value and then take it with JavaScript, like this?
<input type="hidden" id="someId" value"#some.Id" />
<script type="text/javascript">
var variable = $('#someId').val();
</script>
EDIT:
#{
var formVariables = serializer.Serialize(new
{
id = Model.Id,
name = Model.Name,
age = Model.Age
});
<input type="hidden" id="header_variables" value="#formVariables"/>
<script type="text/javascript" src = "/Scipts/..."></script>
}
Is this good solution?
I personally would go with an extension of the 2nd option and create a seperate .js file. The reason being, if you delegate work out to a 3rd party to take care of the jquery/javascript parts of the UI, then they need not have any sight of the backend functionality.
There are a variety of ways to use html5 attributes (i.e. data-attribute='foo') on the inputs which would allow you to 'decorate' your inputs with a cargo of properties which could be parsed inside the external .js file.
A very brief example:
in your view:
<input type='text' id='myId' data-action='#Url.Action("MyAction")' class='myClass' />
in your .js file:
var targetAction = $('#myId').attr('data-action');
this gives complete separation between the .js and the views. It does require a degree of planning of course.
Hope this helps
Razor will be parsed at server-side and replaced by relevant output. Therefore, in my opinion it is totally indifferent, if you place it in Javascript or HTML - at client side only the output value will be visible. Thus, in the above example I would choose the first option (place it directly in JS), since you will not have the otherwise unnecessary hidden input field.
I don't think there is a correct answer to this question; only pros and cons.
Pros of using Razor in Javascript
Script is bound to your view model; so model changes will get picked up automatically, and errors will get caught at compile time.
Cons
Script is mixed with markup, contrary to web design best practices (put script at the bottom so that it will never break your page).
Script cannot be compiled/minified, because, again, it's mixed in with your markup.

Passing rendered html to a javascript function

I have some html code rendered on the server side. This is passed to a jsp which renders a javascript-call with this html:
<script type="text/javascript">
window.parent.${param.popup_return}("${helpId}", "${content}");
</script>
content is like
"
This is a <p class="xyz">test</p>
"
My problem is that - according to the quotes in 'content' - the javascript-call is wrong as it is rendered to
<script type="text/javascript">
window.parent.${param.popup_return}("ybc", "This is a <p class="xyz">test</p>");
</script>
Does anyone know how I can solve this (besides manually replacing all quotes)?
Use a JSON encoder to create the encoded strings.
But you'll also have to ensure that the output doesn't contain the sequence </ in string literals, which is invalid in a <script> block (</script is the version that will also break browsers).
Many JSON encoders either by default or optionally will encode to <\/ or \u003C/ to avoid this problem.
I use this:
<div id="result" style="display:none">
${content}
</div>
<script type="text/javascript">
window.parent.${param.popup_return}("${helpId}", dojo.byId("result").innerHTML);
</script>
This seems to work perfectly
You aren't using JSTL here (you originally tagged the question with only JSTL). You are using EL in template text. It get printed plain as-is. You'd like to use JSTL core <c:out> to escape predefined XML entities (which also works for HTML in this particular case, quotes is among the escaped XML entities).
window.parent.${param.popup_return}("<c:out value="${helpId}" />", "<c:out value="${content}" />");
An alternative (if you hate that the JSP syntax highlighter or validator bugs/jerks about nested tags/quotes) is the JSTL function fn:escapeXml():
window.parent.${param.popup_return}("${fn:escapeXml(helpId)}", "${fn:escapeXml(content)}");
Have you tried using single quotes instead of double quotes? i.e. changing "${content}" to '${content}'

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