finding something in an array

[ginerjm]

From a little hunting around I found this (no, not from W3):

 

var TMS_evt_names = ["<?php echo join("\", \"", $TMS_evt_names); ?>"];
function chkEvent(i)
{
	choice = document.getElementById("evt"+i).value.toUpperCase();
	alert("in chkevent with "+choice);
	idx = TMS_evt_names.indexOf(choice);
	if (idx < 0)
	{
		alert("invalid event");
		return false;
	}
	else
	{
		alert("found "+TMS_evt_names[choice]);
		return true;
	}
}

 

The array in the first line is being built, since I can see it in my browser.

 

My problem is - when I run it and the function is called, IE tells me the the line with the indexof reference "doesn't support this property of method". I do note that in most examples using indexOf that the arg is a string constant, rather than a variable.  How do I get the variable to work in this instance.  I already tried using "indexOf(choice.value)" but that didn't work either.

[Adam]

That's because indexOf() is a string function, not an array function. You can't actually have an associative array object in JavaScript either, they're all numerically indexed -- the equivalent would require you to use just a plain object. Given you're not trying to assign any keys in the array definition though, I don't see how the choice variable comes into it?

[ginerjm]

Interesting response.  Thanks for pointing it out.  Wonder why that came up in my google search for findgin something in an array?

[ginerjm]

Solved this from a posting I found.

 

var evts = TMS_evt_names.length;
var globalfld = null;
function isValidEvent(obj)
{
	var choice = obj.value.toUpperCase();
	if (choice=='')
		return true;
	var k = evts;
	while (k--)
		if (TMS_evt_names[k] === choice)
			return true;
	alert("' "+choice+" ' is not a valid Event code.");
	obj.value='';
	setFocus(obj);
	return false;
}
function setFocus(elm)
{
	globalfld = elm;
	setTimeout("globalfld.focus();globalfld.select()",100);
}

 

This takes the value of the incoming object (called via "onclick='isValidEvent(this)'" in my html and checks if the value is in my array.  If not, it erases it from the screen and repositions the cursor back on that field.

[Adam]

Ah sorry, there is an indexOf array method. I always thought there wasn't one :S .. Unfortunately though there's no support for it in IE prior to version 9. Using it does keep your code a lot cleaner though, so you could use the prototype object to define it for any browsers that don't already have it:

 

if (Array.prototype.indexOf == null) {
    Array.prototype.indexOf = function(search, fromIndex) {
        var length = this.length;
        var index  = (typeof(fromIndex) !== 'undefined') ? fromIndex : 0;
        for (index; index < length; index++) {
            if (this[index] == search) {
                return index;
            }
        }
    }
}