Language Basics JavaScript DHTML

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  4. Throws error in case of invalid data


Try/Catch



Enter a value: 




function checkValid() {
    try {
        var valueField = document.forms[0]["value"];
        if (valueField.value != "A") {
            throw "It's not what I need";
        }
    }
    catch(errorObject) {
        alert(errorObject);
    }
}
function init() {
    document.forms[0].onsubmit = function() { return checkValid() };
}
window.onload = init;