Description
The indexOf() method is used to returns the first index at which a given element can be found in the array, or -1 if it is not found. The array is searched forwards (front to back).
This method has the form:
Array.indexOf(searchElement[, fromIndex])| Parameter | Description |
|---|---|
| searchElement | (required) Specifies the element to be located in the array |
| fromIndex | (optional) Specifies the index at which to begin the search (default = 0)
If the fromIndex is greater than the length of the array, -1 is returned If the fromIndex is less than zero, the search begins at the offset from the end of the array Note: In all cases, the array is searched from front to back |
Return Value
A Number that indicates the position of searchElement, or -1 if not found
Examples
The following example shows the basic use of this method.
<script>
var cols = [ "Cyan", "Magenta", "Yellow", "Black" ];
document.write(cols.indexOf("Magenta"));
</script>This produces the following result:
Browser Support
| Firefox | IE | Chrome | Opera | Safari |
|---|---|---|---|---|
Version Information
This form was added in version: 1.6
Description
The lastIndexOf() method is used to returns the last index at which a given element can be found in the array, or -1 if it is not found. The array is searched backwards (back to front).
This method has the form:
Array.lastIndexOf(searchElement[, fromIndex])| Parameter | Description |
|---|---|
| searchElement | (required) Specifies the element to be located in the array |
| fromIndex | (optional) Specifies the index at which to start searching backwards (default = array length)
If the fromIndex is greater than the length of the array, the entire array is searched If the fromIndex is less than zero, the search begins at the offset from the end of the array Note: In all cases, the array is searched from back to front |
Examples
The following example shows the basic use of this method.
<script>
var cols = [ "Cyan", "Magenta", "Yellow", "Black" ];
document.write(cols.lastIndexOf("Magenta"));
</script>This produces the following result:
Browser Support
| Firefox | IE | Chrome | Opera | Safari |
|---|---|---|---|---|
Version Information
This form was added in version: 1.6
