Suppose I have a code in string format:
var str = "var a = 10;b = 20;console.log(a+b);";
I need to append this string value to the existing js file(say test.js) dynamically. And also get the result or execute it.
* However, I can load the string in separate and execute it, but that's not what i need. Thanks for your kind help and advice.
You can do it as :
for example in text file you will call a function where you want to append the code as :
test.js ->
// some javascript code
myFunction();
// some javascript code
Now in main file create this function as :
var execuationCode = "var a = 10;b = 20;console.log(a+b);";
function myFunction(){
setTimeout(execuationCode, 0);
}
When nyFunction call in test.js file then it call this main file function
In my HTML file I have linked to the JS with:
src="myscript.js?config=true"
Can my JS directly read the value of this var like this?
alert (config);
This does not work, and the FireFox Error Console says "config is not defined". How do I read the vars passed via the src attribute in the JS file? Is it this simple?
<script>
var config=true;
</script>
<script src="myscript.js"></script>
You can't pass variables to JS the way you tried. SCRIPT tag does not create a Window object (which has a query string), and it is not server side code.
Yes, you can, but you need to know the exact script file name in the script :
var libFileName = 'myscript.js',
scripts = document.head.getElementsByTagName("script"),
i, j, src, parts, basePath, options = {};
for (i = 0; i < scripts.length; i++) {
src = scripts[i].src;
if (src.indexOf(libFileName) != -1) {
parts = src.split('?');
basePath = parts[0].replace(libFileName, '');
if (parts[1]) {
var opt = parts[1].split('&');
for (j = opt.length-1; j >= 0; --j) {
var pair = opt[j].split('=');
options[pair[0]] = pair[1];
}
}
break;
}
}
You have now an 'options' variable which has the arguments passed. I didn't test it, I changed it a little from http://code.google.com/p/canvas-text/source/browse/trunk/canvas.text.js where it works.
You might have seen this done, but really the JS file is being preprocessed server side using PHP or some other language first. The server side code will print/echo the javascript with the variables set. I've seen a scripted ad service do this before, and it made me look into seeing if it can be done with plain ol' js, but it can't.
You need to use Javascript to find the src attribute of the script and parse the variables after the '?'. Using the Prototype.js framework, it looks something like this:
var js = /myscript\.js(\?.*)?$/; // regex to match .js
var jsfile = $$('head script[src]').findAll(function(s) {
return s.src.match(js);
}).each(function(s) {
var path = s.src.replace(js, ''),
includes = s.src.match(/\?.*([a-z,]*)/);
config = (includes ? includes[1].split('=');
alert(config[1]); // should alert "true" ??
});
My Javascript/RegEx skills are rusty, but that's the general idea. Ripped straight from the scriptaculous.js file!
Your script can however locate its own script node and examine the src attribute and extract whatever information you like.
var scripts = document.getElementsByTagName ('script');
for (var s, i = scripts.length; i && (s = scripts[--i]);) {
if ((s = s.getAttribute ('src')) && (s = s.match (/^(.*)myscript.js(\?\s*(.+))?\s*/))) {
alert ("Parameter string : '" + s[3] + "'");
break;
}
}
Whether or not this SHOULD be done, is a fair question, but if you want to do it, http://feather.elektrum.org/book/src.html really shows how. Assuming your browser blocks when rendering script tags (currently true, but may not be future proof), the script in question is always the last script on the page up to that point.
Then using some framework and plugin like jQuery and http://plugins.jquery.com/project/parseQuery this becomes pretty trivial. Surprised there's not a plugin for it yet.
Somewhat related is John Resig's degrading script tags, but that runs code AFTER the external script, not as part of the initialization: http://ejohn.org/blog/degrading-script-tags/
Credits: Passing parameters to JavaScript files , Passing parameters to JavaScript files
Using global variables is not a so clean or safe solution, instead you can use the data-X attributes, it is cleaner and safer:
<script type="text/javascript" data-parameter_1="value_1" ... src="/js/myfile.js"></script>
From myfile.js you can access the data parameters, for instance with jQuery:
var parameter1 = $('script[src*="myfile.js"]').data('parameter_1');
Obviously "myfile.is" and "parameter_1" have to match in the 2 sources ;)
You can do that with a single line code:
new URL($('script').filter((a, b, c) => b.src.includes('myScript.js'))[0].src).searchParams.get("config")
It's simpler if you pass arguments without names, just like function calls.
In HTML:
<script src="abc.js" data-args="a,b"></script>
Then, in JavaScript:
const args=document.currentScript.dataset.args.split(',');
Now args contains the array ['a','b'].
I am preparing an HTML code on memory for an Iframe, when I use append it executes the code.
html = $(parser.parseFromString($("#EHtml").val(), "text/html"));
js = '<script>' + $("#EJs").val() + '</script>';
html.find('body').append(js);
$("#EHtml").val() contains HTML code
and the append function does its job but also executes the code.
Any thoughts here?
You need to just store a reference to the string of code and do 1 of two things: either do the append interaction only when you want to run the code later, or run eval(jsString) when you want to run it.
Script tags won't execute if their [type] attribute is set to anything wacky.
<script type="wacky/non-executing">
console.log("This will not execute! You will not see this!");
</script>
Its Obvious to run script when you insert it, between script tags,Because your DOM already complete loads.
And it will run twice because you put it inside the body So when you body content canges the script ran again!
So you have to set your Script tag on head of an iframe to it will run Only when you insert it or reload,and not again an again !
I am not suggesting you to use eval() because it is dangerous to use for script evaluation,eval() is basically used for another purpose !
Use <script></script> tags to run your script and place it on head if you don't want to ran it twice .
var script = document.createElement('script');
script.innerHTML = $("#EJs").val();
iframe.contentWindow.document.head.appendChild(script);
May be this will help you..
Try using entities, like
var encodeHtmlEntity = function(str) {
var buf = [];
for (var i=str.length-1;i>=0;i--) {
buf.unshift(['&#', str[i].charCodeAt(), ';'].join(''));
}
return buf.join('');
};
html.find('body').append(encodeHtmlEntity(js));
to append and
var decodeHtmlEntity = function(str) {
return str.replace(/&#(\d+);/g, function(match, dec) {
return String.fromCharCode(dec);
});
};
decodeHtmlEntity(html.find('body').val());
to read.
Got it in the way I need.
I was trying to add the script tag without using ways around the problem - I mean I just wanted to add the tag as it is. Thanks every body for the inputs - I got the solution from your advises...
in the end I could append to the Iframe but it was executing in the main page context. What was causing the problem was using JQuery to do the appending... so here it is:
frame = document.getElementById("frame");
out = (frame.contentWindow) ? frame.contentWindow : (frame.contentDocument.document) ? frame.contentDocument.document : frame.contentDocument;
out.document.open();
out.document.write(html.find('html')[0].outerHTML);//HTML added here
//JS appended here
js=out.document.createElement('script');
js.innerHTML = 'js code here';
out.document.getElementsByTagName("body")[0].appendChild(js);
out.document.close();
I hope its useful for someone...
I have a server-side script but now I want it run on client-side, so I want to convert from php to javascript. I am really not good at js so, please help.
Php code here:
function getAlexaRank($theUrl)
{
$alexa_url = "http://data.alexa.com/data?cli=10&dat=snbamz&url=" . $theUrl;
$doc = new DOMDocument();
$doc->load($alexa_url);
$popularities = $doc->getElementsByTagName("POPULARITY");
foreach($popularities as $popularity)
{
return $popularity->getAttribute('TEXT');
}
return "-1";
}
Refer to the following link to acheive it using js
http://www.hiteshagrawal.com/javascript/javascript-parsing-xml-in-javascript
Is it possible from a Javascript code to find out "where" it came from?
I needed this to provide scripts that could run folder-agnostic, e.g.:
http://web1/service-a/script.js
http://web2/some-folder/service-b/script.js
And they're linked in:
http://web1/page1.html
http://web2/page2.html
The file script.js is identical in both locations but I would like them to be able to find out where it originates from so it can call the right web service methods (script.js from service-a should call service-a.method while script.js that is served from service-b should call service-b.method)
Is there a way to find out where script.js came from without using any server-side code?
Well, it's kind of a hack, you could grab all the <script> tags in the document, look at which one has the file name of the file, and do the logic from there.
document.getElementsByTagName('script'); is pretty much all you need. The rest is basic JS.
Even more interesting than looping through all of the returned elements (although that's probably safest), is that we can simply only look at the last element returned by the call above, as Javascript guarantees that must be the <script> tag we're in at the time of it being parsed (with the exception of deferred scripts). So this code:
var all_scripts = document.getElementsByTagName('script');
var current_script = scripts[all_scripts.length-1];
alert(current_script.src);
Will alert the source of the script tag used to include the current Javascript file.
You can analyze source of the html where script.js is included for tag and retrieve path of the script.js from there. Include next function in script.js and use it to retrieve the path.
function getPath() {
var path = null;
var scriptTags = document.getElementsByTagName("script");
for (var i = 0; i < scriptTags.length; i++) {
var scriptTagSrc = scriptTags.item(i).src;
if (scriptTagSrc && scriptTagSrc.indexOf("script.js") !== -1) {
path = scriptTagSrc;
break;
}
}
return path;
}