CODEWITHSUNDEEP
javascriptjqueryfunctionif-statement
user5030211
user5030211

Reputation:

test for null not working

I have a an onclick function, inside this function I want to create a condition for the way some elements are shown in the textarea. added this in the function:

    bPlace = bookForm.txtPlace.value;
    if (bPlace="null") {
        bPlace="!."
    }

bookForm.myText.value = bPlace

according to this condition when the value in txtPlace in myForm is not null it should show anything the user puts in. But when I test it, when I type something, instead of showing that, it still shows the (( !. )) in the textarea.

I should say I used "Undefined" instead of Null and still the same thing happened

Can you please tell me what am I doing wrong?

Upvotes: 0

Views: 44

Answers (1)

Arun P Johny
Arun P Johny

Reputation: 388416

The problem is you are using assignment operator instead of comparision operator

The statement bPlace="null" will assign the string null to bPlace and will return it, which is a truthy value so the if block will always get executed.

bPlace = bookForm.txtPlace.value;
if (bPlace == "null") {
    bPlace = "!."
}

bookForm.myText.value = bPlace

But since bPlace is a input value, I think what you are trying to do is if the input is left blank you want to put a default value in that case you can check

bPlace = bookForm.txtPlace.value;
if (!bPlace) {
    bPlace = "!."
}

bookForm.myText.value = bPlace

Demo: Fiddle

Which can be further shorten to

bookForm.myText.value = bookForm.txtPlace.value || '!.';

Demo: Fiddle

Upvotes: 3

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