function check_extensions(allowedExtensions, element_name, span_element_name, class_name){
	var element = document.getElementById(element_name);
	var span_element = document.getElementById(span_element_name);
	if (element.value.length > 0) {
		var found = false;
		for (i = 0; i < allowedExtensions.length; i++) {
			if (element.value.toLowerCase().lastIndexOf("." + allowedExtensions[i]) != -1) {
				found = true;
				break;
			}
		}
		
		if(!found){
			alert("Doar fisierele de tip : " + allowedExtensions.join(", ") + " sunt acceptate!");
			
			var extensions = "new Array('" + allowedExtensions.join("', '") + "')";
			span_element.innerHTML = "<span id=\"" + span_element_name + "\"><input type=\"file\" class=\"" + class_name + "\" id=\"" + element.name + "\" name=\"" + element.name + "\" size=\"40\" onchange=\"check_extensions(" + extensions + ", '" + element.name + "', '" + span_element_name + "', '" + class_name + "')\"></span>";
			//alert(span_element.innerHTML);
			
			return false;
		}
	}
}