Question

-7

Javascript String Compare == sometimes fails

rated 0 times [ 0] [ 7] / answers: 1 / hits: 114418 / 15 Years ago, thu, may 14, 2009, 12:00:00

How could the following code sometimes evaluate to false?

(transport.responseText == '1' || 

 transport.responseText == 'CARD_VALID')

My JavaScript code:

if (transport.responseText == '1' || 

    transport.responseText == 'CARD_VALID') {

    // do something.

}

else if (transport.responseText == 'CARD_INVALID' || 

             transport.responseText == 'INVALID_CHECKSUM') {

    // do something else....

}

else {

    new Ajax.Request('/report_error.php?responseText='+transport.responseText);

    // report error to user

}

What could cause JavaScript string compare == to return false when the strings are identical?

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

seth

Add To Favorites

Follow

Total Points: 307

Total Questions: 114

Total Answers: 96

Location: Kenya

Member since Mon, Jun 14, 2021

3 Years ago

seth questions

1 NextJS: Reload iFrame from another component

Tue, Feb 8, 22, 00:00, 2 Years ago

1 Storybook not showing styles

Thu, Dec 24, 20, 00:00, 3 Years ago

1 Debugging with VSCODE not working in a Webpack + Typescript + no-framework

Mon, May 18, 20, 00:00, 4 Years ago

1 How to set dynamic html tag according to props in Svelte

Sun, Apr 19, 20, 00:00, 4 Years ago

1 Unable to pass props in Next

Thu, Apr 9, 20, 00:00, 4 Years ago

View All

answered 15 Years ago arturo · Accepted Answer

Double equals is the appropriate way to compare strings in Javascript, it is returning false then there may be whitespace to the left and or right of one string.

Put a .trim() on the end of the strings and my comparison should started working:

var panel = response.substr(0, response.indexOf(<)).trim();

if(panel == combo){

    //do something

}