Question

Im sure I have missed something obvious but any idea why the following addEventListener code is firing everywhere (on not just on the submit button)?

HTML:

    <form action="#">
        <input type="text"><br>
        <input type="text"><br>
        <button id="submit">submit</button><br>
    </form>

JS:

    function validate () {
        var inputs = document.getElementsByTagName( input );
        var inputs_length = inputs.length-1;
        for (i=0; i<=inputs_length; i++) {
            var inputs_value = document.getElementsByTagName( input )[i].value;
            if (inputs_value == "") {
                alert( there is a text box empty );
            }
        }

    }   

    var el = document.getElementById( submit );

    if (el.addEventListener) {  
        el = addEventListener( click , validate, false);   
    } else if (el.attachEvent)  {  
      el.attachEvent( onclick , validate);  
    }

缩略语

el = addEventListener( click , validate, false);

el.addEventListener( click , validate, false);

MY TYPO:

Answer 1

修改:

if (el.addEventListener) {  
    el = addEventListener( click , validate, false);

为此:

if (el.addEventListener) {  
    el.addEventListener( click , validate, false);

Answer 2

冗长的评论。

在您的法典中:

    // inputs is an HTMLCollection of all the inputs
    var inputs = document.getElementsByTagName( input );

    // No need for the -1
    var inputs_length = inputs.length;

    // Don t forget to declare counters too, very important
    // Just use < length
    for (var i=0; i<inputs_length; i++) {

        // Instead of this very inefficient method
        var inputs_value = document.getElementsByTagName( input )[i].value;

        // use the collection you already have
        var inputs_value = inputs[i].value;

        if (inputs_value == "") {
            alert( there is a text box empty );
        }
    }

最好在开始时宣布<代码>投入-价值<>代码>,这样所有申报都放在一个地方,但因为你没有有害。

Oh,没有给出一个形式要素,即“提交书”(或任何其他形式)的名称或背书,因为它将给同一名称的形式方法蒙上阴影,因此可以被称作。

友情链接