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Here is interesting puzzle


Rachit Shah

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I have been trapped in a puzzle. I want to retrieve the script code from the same html page and put it inside script tags. I have put button function which fetches the script in the page.While fetching script code I encountered below mentioned scenario. Here in the Original code its giving me error as unterminated string constant.I changed script as shown in second quoted code. Now its working. I did not figure out why its giving error in first case (i.e first code).Original code

<html><head><script id='script1' name='script1' type="text/javascript">function writeIt () { var x= "<script>" + window.document.scripts(0).text; x = x + "</script>"; alert(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write"/></body></html>
Changed code
<html><head><script id='script1' name='script1' type="text/javascript">function writeIt () { var x= "<script>" + window.document.scripts(0).text; x = x + "</script"; x = x + ">"; alert(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write"/></body></html>
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Basically because it reads the </script> and terminates the code.  If you did <\/script> it'll read it fine :)

I think thats not true. Check the code below. Its working fine. The </head> is there, the browser iss not reading it?
<html><head><script id='script1' name='script1' type="text/javascript">function writeIt () {var x="";x = x + "<html>\n<head>\n";x= x + "<script>" + window.document.scripts(0).text;x = x + "<\/script>\n";x = x + "</head>\n<body>\n";x = x + document.body.innerHTML;x = x + "\n</body>\n</html>";alert(x);document.close(); // or document.open();document.write(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write"/>rachit</body></html>
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<html><head><script id='script1' name='script1' type="text/javascript">function writeIt () {var x="";x += "<html>\n<head>\n";x += "<script>" + window.document.scripts(0).text;x +=  "<\/script>\n";x += "<\/head>\n<body>\n";x += document.body.innerHTML;x += "\n<\/body>\n<\/html>";alert(x);document.close(); // or document.open();document.write(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write"/>rachit</body></html>

Loads fine for me. I backslashed the head, body and html and tidied, although they weren't neccessary changes.

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If I change <\/script> to </script> its giving error.If I change <\/head> to </head> its not giving error. Why? Why? Why?Here is the working code. Its working fine. The above scenario is visible here. I have put it in red.

<html><head><script id='script1' name='script1' type="text/javascript">function writeIt () {var x="";x = x + "<html>\n<head>\n";x= x + "<script>" + window.document.scripts(0).text;x = x + "<\/script>\n";x = x + "</head>\n<body>\n";x = x + document.body.innerHTML;x = x + "\n</body>\n</html>";alert(x);document.close(); // or document.open();document.write(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write"/>rachit</body></html>
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Hah! Got it. Try this. And I modified Blue's script, by the way.

<html><head><script id="script1" name="script1" type="text/javascript">function writeIt (){var x="";y=document.getElementsByTagName("script");x += "<html>\n<head>\n";x += "<script>" + y[0].innerHTMLx +=  "<\/script>\n";x += "<\/head>\n<body>\n";x += document.body.innerHTML;x += "\n<\/body>\n<\/html>";alert(x);document.close(); // or document.open();document.write(x);}</script></head><body><input type="button" onclick="writeIt()" value="Write" />rachit</body></html>

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Ahh, I think I understand now.Blue, on that topic, is correct. The moment the javascript rights </script>, the script is terminated, because the javascript thinks it's been terminated. The browser interprates it as a dynamic change of the length of the script, and closes the function/whatever the script is doing at the moment. That's your problem.

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Thanx for all that you have discussed here in this thread. It cleared a cruicial understanding of how javascript may parse the script.HTML/Javascript is like my hobby/interest.If I come to know something offbeat (advanced technical details) about javascript/HTML then I think I would accumulate advanced knowledge.I would say I have intermediate level understanding in HTML/Javascript. I want to be advanced in this topic and that was the reason I joined this forum. Dont take literal meaning of "offbeat". I dont mean unusual, I mean advanced or tricky.

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