I want to extract a new objects information name and arguments into a HTML page.
Such as
<script>
var a = new g(10,20);
</script>
I need to print :
new object g with arguments 10,20
I am newbie to Webkit.
Initially I thought just add a printf statement in the javascriptcore. I added some printf statements to
JavaScriptCore/runtime/FunctionConstructor.cpp ,ObjectConstructor.cpp .
But didn't get right result .
I googled but there is few tutorials about javascriptcore.
I hope some expert can point me in the right direction .
I'm not sure which version of WebKit are you hacking with, so my solution may not work.
I suggest you to add logging statements in Interpreter.cpp, inside the block of DEFINE_OPCODE(op_construct).
Related
I'm trying to use JavaScript to include a footer on several webpages, so if I want to change the footer, I only have to change it in one place. PHP is not available on this server and neither are server side inserts (SSI), but Perl, Python, and Tcl are available. I have been trying with document.getElementsByTagName('footer').innerHTML = "text"; but it doesn't produce text. I copied this code from dev.mozilla, and it tells me how many tags I have:
var footer = document.getElementsByTagName('footer');
var num = footer.length;
console.log('There is ' + num + ' footer in this document');
So, I don't know what's wrong with the innerHTML script. I also tried with paragraph tags and got the same results in both cases.
I reccoment using textContent instead. Se why here.
To see how it works, paste the following into your browser console while you're on StackOverflow and hit enter.
document.querySelector('.site-footer').textContent = 'Custom footer content.'
note: use querySelector with a class instead of getElementByTagName
Cheers! 🍻
Before asking this question, I had searched for Python includes without any luck, so I stopped there, but after asking this question, I thought that I should search for Perl/Ruby includes. Today, I found out that I can use the Perl use function, so I could study that and try to implement it although I am completely new to Perl. Ruby also appears capable, perhaps even more. I have no experience with Ruby either, but maybe I should start there.
I just figured out that getElementsByTagName() results in an array, so I have to refer to the footer's index with [0]:
var footerTags = document.getElementsByTagName('footer');
footerTags[0].innerHTML = "test";
I've been playing with snippets for Atom editor,
and see that I've learned I can include
JavaScript inside of a snippet, as my example shows.
(It inserts a TODO Comment with date)
TODO: (RAM) Fix this - 2014-11-23 20:55
HELLO
How can I include MORE JavaScript.?
For example
inside the snippet to set
var= to something
or
call a JS library
or
ask for input from user i.e. confirm();
and proceed on basis of confirm() function.
Any help would be appreciated, I looked for a long time,
but not much documentation on this. Submlime Text's snippets allowed lots of code to be inserted via Python.
Thanks
~Rob
Inside file snippets.cson
'.source.js':
'Date TODO: insert':
'prefix': 'datetd'
'body': """
TODO: (RAM) $1 - #{datetime = new Date(); datetime.getFullYear()}-#{(datetime.getMonth()+1)}-#{datetime.getDate()} #{datetime.getHours()}:#{datetime.getMinutes()}
#{"hello".toUpperCase(); }
$2
"""
Update: With the merge of atom/atom#4791, the capability of putting CoffeeScript code in CSON configuration files has been removed from Atom. The rest of the answer has been left intact for historic reference.
Actually, the syntax of the file is CoffeeScript (hence .cson as in CoffeeScript Object Notation), not JavaScript. It just so happens that you typed in JavaScript that is allowed as CoffeeScript. CoffeeScript doesn't use the var keyword, so you can assign variables like you did in your example:
datetime = new Date()
The other items, you'll probably have to get a little creative. I don't believe that the snippets package was intended to be used in this manner, which is why the lack of documentation on the "feature".
I am sure there is something simple that I am missing but I am stumped here.
The issue is that I am looping through an array of strings and using the string value to search for a part of that string using indexOf. The first time around the loop the index of is finding what I am looking for but the second time it is not.
Here is a fiddle - http://jsfiddle.net/jeremywrags/uSwjG/1/
the line that seems to be not working is this
var aliasIndex = fromclause.indexOf(" " + tableAlias + " " );
I am trying to build a SQL parser for a cloud app and the use case here is that when a table is aliased I need to get the original table name so that I can look up the table columns. The first time around the loop index of returns the index and then the table name. The second time around the index of is -1 and the table name is not retrieved.
If I need to provide more context please let me know.
thanks
It's not matching because on the second pass, tableAlias is the string " b" (note the space). So then you search for " b " (note two leading spaces), which isn't there.
Rather than using alert, use the debugger built into your browser. You can set breakpoints in the code, step through line by line, inspect variables, etc., etc. Doing that with this would have shown you, when looking at the variable tableAlias, that it had a leading space, hopefully helping you find the solution.
Here's what that looks like in Chrome's debugger, for instance:
(If you look at the jsFiddle source above the actual debugger's version, you'll see a debugger; statement in the code — normally you don't need that statement, you can just open your page, use the "Sources" tab to find your JavaScript file, navigate to the line, and click the margin to the left of it to set a breakpoint. But sometimes [for instance, when using jsFiddle], the debugger; statement is handy. What it does is, if the debugger is open, halts execution of the code at that point like a breakpoint does.)
Hi i am trying to assing this value to a variable in javascript but always get an error. I have no clue what is going on, my statement is something like:
var a = "</script>";
I tried everything but it does not work, what should i do instead??
You need to hide that from the HTML parser:
var a = '</' + 'script>';
If you don't, then the surrounding HTML parser — which knows nothing at all about JavaScript syntax — thinks that that's the end of the script block. After it sees the opening tag for the block, it literally scans for </script> (ignoring case of course).
(edit — though basically right I think, my claim that browsers are searching strictly for </script> is probably somewhat overstated; I suspect that they look for anything that's recognizable as a closing tag. The basic point still stands of course.)
I may be misunderstanding your question but if you are trying to output '' on the screen for the reader (human) to view, then you can use:
var a = "</script>";
Note that this won't work for executable scripts however - it won't be interpreted as a html/script tag.
I'd like to start by saying that my code is working perfectly, this is more a "how best to do it" kind of question.
So I have code like this in my .aspx file:
function EditRelationship() {
var projects=<%= GetProjectsForEditRelationship() %>;
// fill in the projects list
$('#erProjectsSelect').empty();
for(var i in projects)
$('#erProjectsSelect').append('<option value='+projects[i][0]+'>'+projects[i][1]+'</option>');
var rels=<%= GetRelationshipsForEditRelationship() %>;
// etc
}
Again, it's working fine. The problem is that VS2008 kinda chokes on code like this, it's underlining the < character in the tags (with associated warnings), then refusing to provide code completion for the rest of the javascript. It's also refusing to format my document anymore, giving parsing errors. The last part is my worst annoyance.
I could put some of these in evals I guess, but it seems sorta dumb to add additional layers and runtime performance hits just to shut VS up, and it's not always an option (I can't remember off the top of my head where this wasn't an option but trust me I had a weird construct).
So my question is, how do you best write this (where best means fewest VS complaints)? Neither eval nor ajax calls fit this imo.
If your aim is to reduce VS complaints, and if you are running asp.net 4 (supporting Static client Ids), maybe a strategy like the following would be better?
Create a ASP:HiddenField control, set its ClientIdMode to "Static"
Assign the value of GetRelationshipsForEditRelationship() to this field on page load
In your javascript, read the value from the hidden field instead, I assume you know how to do this.
It's more work than your solution, and you will add some data to the postback (if you perform any) but it won't cause any VS complaints I guess :)
You could do this from your page in the code-behind
ClientScript.RegisterArrayDeclaration("projects", "1, 2, 3, 4");
or to construct something like JSON you could write it out
ClientScript.RegisterClientScriptBlock(GetType(), "JSONDeclarations", "your json stuff");
UPDATE Based on my comment
<script id="declaration" type="text/javascript">
var projects=<%= GetProjectsForEditRelationship() %>;
var rels=<%= GetRelationshipsForEditRelationship() %>;
</script>
<script type="text/javascript">
function EditRelationship() {
// fill in the projects list
$('#erProjectsSelect').empty();
for(var i in projects)
$('#erProjectsSelect').append('<option value='+projects[i][0]+'>'+projects[i][1]+'</option>');
}
</script>
I don't have VS2008 installed to test with, so take this with a grain of salt, but have you tried something like this?
var projects = (<%= GetProjectsForEditRelationship() %>);
Something like that might trick the JavaScript parser into ignoring the content of your expression.
For what it's worth, VS2010 correctly parses and highlights your original code snippet.
Is it an option to move this to VS2010? I just copied and pasted your code and the IDE interpreted it correctly.
The best solution is to put javascript in a separate file and avoid this entirely. For this particular function, you're doing server-side work. Why not build the list of options that you intend to add dynamically in codebehind, put them in a hidden div, and then just have jQuery add them from the already-rendered HTML?
If you have a situation where you really want to dynamically create a lot javascript this way, consider using ScriptManager in codebehind to set up the variables you'll need as scripts and register them, then your inline script won't need to escape
ScriptManager.RegisterClientScript("projects = " + GetProductsForEditRelationship());
(Basically, that is not the complete syntax, which is context dependent). Then refer to "projects" in your function.
(edit)
A little cleaner way to do this on a larger scale, set up everything you need like this in codebehind:
string script = "var servervars = {" +
"GetProductsForEditRelationship: " + GetProductsForEditRelationship() +
"GetRelationshipsForEditRelationship: " + GetRelationshipsForEditRelationship() +
"}"
and refer to everything like:
servervars.GetProductsForEditRelationship
If you do this a lot, of course, you can create a class to automate the construction of the script.