Archived:JavaScript halted with "script is too big" error causing Symbian Web Runtime app freeze (Known Issue)
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Overview
Running heavy scripts causes “script is too big” error after 200.000 JavaScript statements on S60 3rd edition feature pack 1, S60 3rd edition feature pack 2 and S60 5th edition devices, excluding Nokia N97 and S60 3.2.2 devices which have the browser version 7.1 or later.
Description
There is a 200.000 limit in the JavaScript statement count in Web Runtime environment. Any heavy script, for example commonly used MD5 JavaScript algorithm, is halted after too many successive calls, resulting into a “script is too big” error and freeze of the widget. This will especially affect execution of complex and long running widgets.
How to reproduce
Download MD5 JavaScript algorithm and create following test harness. Execute it and let it iterate approximately 530 times.
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function startLoop() {
textArea = document.getElementById("text");
var counter = 0;
var next = function(){
var str = Math.round(Math.random()*1000)+"";
try{
var md5str = hex_md5(str);
}
catch (err) {
alert(err);
}
++counter;
textArea.innerHTML = counter + ": " + str + "<br>MD5:" + md5str;
setTimeout(next, 50);
}
next(); //start the endless loop
}
Solution
There are ways to reset the JavaScript statement counter. Calling setTimeout with a string instead of a function pointer forces the parser to parse the string and also to reset the execution counter. Call setTimeout("void()",0); in areas of the widgets that are executed frequently. Alternatively setInterval can be used to achieve the same, with interval like 5 seconds and a call to void(): setInterval("void()",5000);
This problem does not impact Nokia N97 device or S60 3.2.2 devices which have the browser version 7.1 or later. Upcoming firmware updates for older devices may include a fix. Therefore it is recommended to include this fix in the Web Runtime widgets just in case.
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