jQuery.inArray（），即使它包含数组中的值，也返回-1

Question

The inarray function returns -1 even if it has the value in my array for eg. if I have ['3','7','43','44','45','46'] in my array, when I select a value 3 or 7 it shows correct answer and then when I select other values it returns -1.

my jQuery coding:

$(document).on("change", '#level',function() {
  var valu = $('#level').val(); 
  $.each(filterResults, function(index, item) {
    if(jQuery.inArray(valu , item.id)!==-1){ //item.id has all array values
      //my functions
      }
    }
});

then my HTML coding

<select class="tb2" name="level" id="level">
  <option value="">Select Level</option>
  <option value="3">Pre Test</option>
  <option value="7">Level 1</option>
  <option value="43">Level 2</option>
  <option value="44">Level 3</option>
  <option value="45">Level 4</option>
  <option value="46">Level 5</option>
</select>

console.log(valu,item.id) returns

44 3

44 7

44 43

44 44

44 45

44 46

Answer 1

Try

if(jQuery.inArray(valu , filterResults)!==-1)

without .each()

 var filterResults = ['3','7','43','44','45','46']; $(document).on("change", '#level',function() { var valu = $('#level').val(); // $.each(filterResults, function(index, item) { if(jQuery.inArray(valu , filterResults)!==-1){ //my functions console.log(valu, $.inArray(valu, filterResults)) } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"> </script> <select class="tb2" name="level" id="level"> <option value="">Select Level</option> <option value="3">Pre Test</option> <option value="7">Level 1</option> <option value="43">Level 2</option> <option value="44">Level 3</option> <option value="45">Level 4</option> <option value="46">Level 5</option> </select> 

Answer 2

item.id does not contain an array, but a single id . $.inArray only works with arrays. Try this instead:

$(document).on("change", '#level',function() {
   var valu = $('#level').val(); 
   $.each(filterResults, function(index, item) {
       if(valu == item.id){ // if item.id is equal to valu (e.g. '7' == '7')
           // some code
       }
   });
});

Alternatively, you could filter the results using $.grep() to find out if the id is in there:

$(document).on("change", '#level',function() {
   var valu = $('#level').val(); 
   if( $.grep(filterResults, function(){return this.id == valu}).length ){
       // some code
   }
});

Answer 3

ok, the problem in your code is that you are iterating through the results array for no reason. $.inArray, will already iterate though the array without you having to do the work; if the value exists, it will return the index of the item, if not, it will return -1. With that being said, this is what you should do:

var filterResults = ['3', '7', '43', '44', '45', '46'];
$('#level').change(function() {
    var value = $(this).val();
    if ($.inArray(value, filterResults) > -1) { 
        console.log(value + " EXISTS IN ARRAY");
    } else {
        console.log("FALSE");
    }
});

Here's a FIDDLE for further help.