How to specify (and/or) conditions in Javascript?

[Fernie]

How do you specify an and/or condition in javascript? I can specify a
condition as follows:

if (var = 'text1')
{
alert('the variable is equal to text1');
}


What I'd like to do is add an 'or' condtion but I get a syntax error:

if (var = 'text1' or var = 'text2')
{
alert('the variable is equal to either text1 or text2');
}


Thanks in Advance,

Fernie

 

[Philip Ronan]

How do you specify an and/or condition in javascript? I can specify a
condition as follows:

if (var = 'text1')
{
alert('the variable is equal to text1');
}

YOU WRONG!!!

if (var == 'text1')
{
alert('the variable is equal to text1');
}

What I'd like to do is add an 'or' condtion but I get a syntax error:

if (var = 'text1' or var = 'text2')
{
alert('the variable is equal to either text1 or text2');
}

YOU WRONGER!!!

if (var == 'text1' || var == 'text2')
{
alert('the variable is equal to either text1 or text2');
}

(When's "Banzai!" coming back to Channel 4, I wonder?)

 

[Fernie]

Philip,

Thank you for correcting me.

Best Regards,

Fernie

 

[C A Upsdell]

YOU WRONGER!!!

if (var == 'text1' || var == 'text2')
{
alert('the variable is equal to either text1 or text2');
}

Better would be:

if ( (var == 'text1') || (var == 'text2') )
{
alert('the variable is equal to either text1 or text2');
}

because, as the OP is a newbie at this, he/she will likely have problems
regarding which operators bind more closely, and so should get into the
habit of using parentheses to make sure the code does what they expect, even
when, as in the example above, extra parentheses are superfluous.

 

[Fernie]

Thanks for the suggestion.

Better would be:

if ( (var == 'text1') || (var == 'text2') )
{
alert('the variable is equal to either text1 or text2');
}

because, as the OP is a newbie at this, he/she will likely have problems
regarding which operators bind more closely, and so should get into the
habit of using parentheses to make sure the code does what they expect,
even when, as in the example above, extra parentheses are superfluous.

 

[Joel Shepherd]

YOU WRONG!!!

Easy, big fella... ;-)

if (var == 'text1')

Right. One way of guarding against the relatively common programmer's
error of typing "=" when "==" is meant, is to make a habit of putting
the constant (or, the expression that can't be assigned to) on the
left-hand side of the operator. E.g.,
if ('text' == var)

Accidentally writing that as
if ('text' = var)

is bound to set off alarms, though I'm not sure if they'd be at
compile-time (hopefully) or later in JavaScript.

 

[Michael Winter]

[snip]

Accidentally writing [...]
if ('text' = var)

is bound to set off alarms, though I'm not sure if they'd be at
compile-time (hopefully) or later in JavaScript.

ECMAScript is an interpreted language, so there is no compilation phase.
Fatal syntax errors should be signaled when the script is parsed as the
document loads.

Mike