Question

<script>
    function loop()
    {
        var input = document.getElementById('id').value;
        //var ans;
        for (var x = 1; x < input; x++)
        {
            var ans = document.getElementById('hello').innerHTML;
        }
    }
</script>
<input type="text" id="id" />
<input type="submit" onclick="loop()" value="isubmit">
<div id="hello"></div>

我需要在文本字段中输入数字然后提交它，然后它将显示循环。出于某种原因，我只得到白屏。它什么都不做。

Answer 1

如果您想要做的是从1到输入的数字减去1，那么您可以将您的功能修改为：

function loop() {
  var input = document.getElementById('id').value;
  var result = document.getElementById('hello');
  for (var x = 1; x < input; x++) {
    result.innerHTML += x + ' ';
  }
}

检查这个小提琴，看看它的实际效果：http://jsfiddle.net/arnellebalane/1ysut9L3/

Answer 2

HTML

<input type = "text" id = "input_id" />
<input type = "submit" id = "submit_btn" value = "isubmit">

<div id = "hello">
    ...
</div>

的JavaScript

function LoopOnClickEvent(input_id, button_id, result_id)
{
    input = document.getElementById(input_id);
    button = document.getElementById(button_id);
    result = document.getElementById(result_id);

    button.onclick = function()
    {
        var val = parseInt(input.value);

        if(Number.isNaN(val) || val < 2)
        {
            var old = result.innerHTML;
            result.innerHTML = "Please type a real number greater than 1"; 
            setTimeout(function(){ result.innerHTML = old; }, 1500);
        }
        else
        {
            var final_val = "";
            for(var cpt = 1; cpt < val; ++cpt)
            {
                final_val += cpt;
            }
            result.innerHTML = final_val;
        }
    };
}

/* Exemple */
LoopOnClickEvent("input_id", "submit_btn", "hello");

http://jsfiddle.net/q0f4g5gr/

我希望它会对你有所帮助:)。

Javascript在表单中输入一个数字

2 个答案: