Uncaught ReferenceError: e is not defined

Question

3.00/5 (2 votes)

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in this code :

JavaScript

m.port1.onmessage = function (e) {

alert(e.data);
                                 }

i want done wen e is defined !
for exam like this :

while (e == define)
{
//do more
}

Posted 22-Nov-14 20:34pm

‫محم د‬‎

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Comments

SrikantSahu 23-Nov-14 2:49am

Not sure, what is expected here.
However, if we want to check whether e is defined or not, we generally use typeof.

Example:
if(typeof e === "undefined") {
alert(1);
}
else {
alert(2);
}

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**Joezer BH** · Accepted Answer · 2014-11-22T21:10:00

Solution 1

You can use this code to verify that a variable is defined (or undefined)

JavaScript

// In your case instead of "variable" you will of course use "e"
if (typeof variable === 'undefined') {
    // variable is undefined
}

Cheers,
C

Posted 22-Nov-14 21:10pm

Joezer BH

Updated 22-Nov-14 21:11pm

v2