I want to ask a question why this is not working?
var a = $('input').attr('value').split(',');
if(a instanceof Array) alert(1);
if($.inArray($('#id').text(), a)) alert(2);
if($.inArray('United State', a)) alert(3);
// a is array but no return correct match.
I split a value into array and use $.inArray to check where a string has in the array.
But it will not return correct index.
I dont know what is wrong in the example. Please advice.
Thank you very much.
From the DOCS :
Because JavaScript treats 0 as loosely equal to false (i.e. 0 == false, but 0 !== false), if we're checking for the presence of value within array, we need to check if it's not equal to (or greater than) -1.
so :
if( $.inArray($('#id').text(), a) != -1) alert(2);
$.inArray returns index of the element found in the given array (or -1 if not found).
As an example,
$.inArray("United State", ["United State", "America"]) === 0
$.inArray("Unknown", ["United State", "America"]) === -1
So, in order to check if the element exists in the array you have to use:
if ($.inArray("Unknown", ["United State", "America"]) > -1) {
// ...
}
The $.inArray() method is similar to JavaScript's native .indexOf() method in that it returns -1 when it doesn't find a match. If the first element within the array matches value, $.inArray() returns 0.
Because JavaScript treats 0 as loosely equal to false (i.e. 0 == false, but 0 !== false), if we're checking for the presence of value within array, we need to check if it's not equal to (or greater than) -1.
Read more here: http://api.jquery.com/jQuery.inArray/
Is the search term the first element in your array by any chance? This would return 0, which javascript treats as false. Your if statement should be:
if($.inArray($('#id').text(), a) < 0) alert(2);
Read the documentation http://api.jquery.com/jQuery.inArray/
Arrays from a split are 0 based indexed, and the string you are asking for is the first one, so it returns a 0 value - which is falsy, so your alerts inside the conditional do not fire because you are getting the 0 index from the inArray.
change your input value to "fred,United State, America" and you will see it alert.
