logical and operator not working properly in javascript

Question

i am checking certain condition in documnet.ready and && operator is not working code snippet lblvalue is empty.

$(function () {
 var lblValue = $("#lblRadioText").text();
    if (lblValue.length > 0 && hasWhiteSpace(lblValue) > 0) {
        $("#rdExportLastTime").css('display', 'inline');
    }
});

function hasWhiteSpace(text) {
    return text.indexOf(' ') >= 0;
}

can you tell me what is wrong.

try if ((lblValue.length > 0) && (hasWhiteSpace(lblValue) > 0)) { so that both statements are enclosed within their own parentheses. — martincarlin87
– martincarlin87, Commented Nov 25, 2011 at 10:31
try this ...if (lblValue.length > 0 && (hasWhiteSpace(lblValue) > 0)) { — balaphp
– balaphp, Commented Nov 25, 2011 at 10:32

Richard Dalton · Accepted Answer · 2011-11-25 10:31:26Z

4

You are trying to check if your boolean value is great than 0.

You don't need the 2nd > 0:

if (lblValue.length > 0 && hasWhiteSpace(lblValue)) {
    $("#rdExportLastTime").css('display', 'inline');
}

Actually, that doesn't make any difference to the operation but it's still not needed.

The code seems to work fine to me (slightly adapted for testing): http://jsfiddle.net/infernalbadger/ZGAj5/1/

answered Nov 25, 2011 at 10:31

Richard Dalton

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jAndy · Accepted Answer · 2011-11-25 10:31:33Z

3

You're returning a boolean value out of hasWhiteSpace(), so you should skip the > 0 in your conditional.

answered Nov 25, 2011 at 10:31

jAndy

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Anders Abel · Accepted Answer · 2011-11-25 10:32:33Z

0

Are you sure that it is operator && that fails?

What if you rewrite your code to:

var lblNotZero = lblValue.length > 0;
var hasWhiteSpace = hasWhiteSpace(lblValue) > 0;
if(lblNotZero && hasWhiteSpace)
{
  $("#rdExportLastTime").css('display', 'inline');
}

Now set a breakpoint (or output using alert) to check the values of lblNotZero and hasWhiteSpace.

Whenever you suspect language fundamentels such as && not working correctly, rethink. Those are extremely well tested.

answered Nov 25, 2011 at 10:32

Anders Abel

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