I thought it was a straight forward concept...but for some reason I can't get it to work.

<script src="Components/JavaScripts/JavaScripts_Main.js" type="text/javascript"></script>
<script type="text/javascript">
function js_ValidateField_BaseCost(p_objTextBoxObject) {
 if (js_IsNumeric(p_objTextBoxObject.value)) {
 p_objTextBoxObject.value = js_ToCurrency(p_objTextBoxObject.value);
 }
}
</script>

In the above code, I have an alert command immediately before the IF statement that works fine (for some reason the "alert" code doesn't appear on here when I post the code), but the if statement below it doesn't. It seems that the code cannot find the js_IsNumeric() function. But if I copy the function from the file, and place it directly on the page, it works. Why isn't the SRC include working?