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Thread: Selectbox

  1. #1
    New Coder
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    Selectbox

    Hi,
    I need a sample coding for selectbox validation. If the user clicks the button without choosing any item in select box an alert should display. Thank you.

    Balen

  • #2
    Supreme Master coder! Philip M's Avatar
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    An options[] array has a property called selectedIndex that contains the index number of the item currently selected.

    function show(){
    var picked = document.form.selectName.selectedIndex;
    alert (picked);
    if (picked.value ==-1) {
    alert ("You must select an option!");
    }
    }

  • #3
    Supreme Master coder! glenngv's Avatar
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    selectedIndex as you said is a number, why did you do picked.value when picked is the value of the selectedIndex? It should be:
    Code:
    if (picked == -1)
    But if the combobox has no size defined or size is 1, selectedIndex will never be -1 as there will always be a selected item. Usually the first item is a dummy option saying "-Please Select-" to signify no selection. So you should check if selectedIndex is 0 not -1.
    Code:
    if (picked == 0)
    Glenn
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