Търсене в помощните статии

Избягвайте измамите при поддръжката. Никога няма да ви помолим да се обадите или изпратите SMS на телефонен номер или да споделите лична информация. Моля, докладвайте подозрителна активност на "Докладване за злоупотреба".

Научете повече

JavaScript for loop ends prematurely when using String.length, why?

  • 6 отговора
  • 2 имат този проблем
  • 12 изгледи
  • Последен отговор от awasen

more options

Ok, I have this JavaScript code:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

//current.value contains, e.g. /tmp/myFile.txt

var filename = "";

var tmp = "";

for (var j = 0; j < current.value.length; j++) {

tmp = current.value.substr(current.value.length-j,1);

if (tmp.length > 0) {

if ((tmp.charCodeAt(0) == 92) || (tmp.charCodeAt(0) == 47)) break;

filename = tmp + filename;

}

}

alert(filename);

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I want to get the file name out as "myFile.txt". This works fine in IE8 & 9, Chrome and Opera, but not in FireFox 4. In FF4 I always get "yFile.txt" as the loop ends one position sooner than all the other browsers.

(And, yes, I know this can be done using reg.exp. but due to a PHP bug I can not use the reg.exp. expression using \\ (double back-slashes) so I had to come up with a work-around).

Regards, Anders

Ok, I have this JavaScript code: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ //current.value contains, e.g. /tmp/myFile.txt var filename = ""; var tmp = ""; for (var j = 0; j < current.value.length; j++) { tmp = current.value.substr(current.value.length-j,1); if (tmp.length > 0) { if ((tmp.charCodeAt(0) == 92) || (tmp.charCodeAt(0) == 47)) break; filename = tmp + filename; } } alert(filename); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I want to get the file name out as "myFile.txt". This works fine in IE8 & 9, Chrome and Opera, but not in FireFox 4. In FF4 I always get "yFile.txt" as the loop ends one position sooner than all the other browsers. (And, yes, I know this can be done using reg.exp. but due to a PHP bug I can not use the reg.exp. expression using \\ (double back-slashes) so I had to come up with a work-around). Regards, Anders

Променено на от cor-el

Всички отговори (6)

more options

Try posting at the Web Development / Standards Evangelism forum at MozillaZine. The helpers over there are more knowledgeable about web page development issues with Firefox.
http://forums.mozillazine.org/viewforum.php?f=25
You'll need to register and login to be able to post in that forum.

more options

Thanks for taking time to respond!

I have created a thread there instead. Anyone who wants to follow it can find it here: http://forums.mozillazine.org/viewtopic.php?f=38&t=2207267&e=0

Regards, Anders

Променено на от awasen

more options

Maybe it is better to start with j=1 because strings start at 0 until length-1 and substr(current.value.length-0) is not defined.

  • current.value.substr(current.value.length-j,1);
more options

Thanks cor-el, you are correct, but unfortunately the issue is that the loop exits one "revolution" too soon. Like in my sample it bails out one character too soon so "abcd" becomes "bcd"...

Regards, Anders

more options

for (var j = 1; j <= current.value.length; j++)

more options
)

Well, the problem is with this line: if ((tmp.charCodeAt(0) == 92) || (tmp.charCodeAt(0) == 47)) break;

If it finds a front- or back-slash it should bail out from the for-loop. The problem is that it bails out one character too soon...

Regards, Anders