Need help with javascript validation

[David kio]

Please help with my project.


I got a list of Item that can be filled.
But i duno how to validate the 'Quantity' field only and only if the user select an item in the 'Item' field.
The validation on javascript should be done when user clik the submit button.

                        Item :
                        <select id="item1">
			<option>Please Select</option>
                        <option value="i1">item1</option>
                                        .............
                        <option value="i5">item5</option>
			</select>

                        Quantity: <input type="text" name="quantity"/>
                        <br/><input type="submit" value="submit">

[Cole Terry]

Here is my suggestion (it may not be exact but something similar):

item1 = document.getElementById('item1');

if (item1.selectedIndex > 0) {
      quantity1 = document.getElementById('quantity1');
      if (quantity1.value > threshold) {
            // do something...
      }
}

[David kio]

opps, sorry....

Thanks anyway, i just solve the problem already.

    item1 = document.getElementById('i1');  
    if (item1.selectedIndex > 0) {  
    	 
    	
    	quantity1 = document.form.quantity1.value;  
    	if (quantity1==null || quantity1=="")
    	  {
    	  alert("Quantity must be filled out");
    	  return false;
    	  }
    	else
    		return true;
        }  
}</script>