javascript中出现警报后如何停止重新加载页面 [英] how to stop reloading page after alert in javascript

问题描述

当我不选择类别并单击提交按钮时，我想停止重新加载页面.有人可以帮我吗?

i want to stop reloading page when i don't choose category and click on submit button. can anybody help me?

function check() {
  var select = document.getElementById("category").value;
  if (select == -1) {
    return alert("You didn't choose category !!!");
  }
}

<form action="#" method="POST" id="form" name="form">
  <select name="category" id="category">
        <option value="-1">Select category</option>
        <option value="1">News</option>
        <option value="2">Sport</option>
        <option value="3">World</option>
        <option value="4">Music</option>
    </select>
  <input type="submit" value="submit" id="submit" name="submit" onclick="check();" />
</form>

推荐答案

您需要从函数中返回 false ，以防止表单被提交.

You need to return false from the function to prevent the form from beeing submitted.

<input type="submit" value="submit" id="submit" name="submit" onclick="return check();" />

function check() {
    var select = document.getElementById("category").value;
    if (select == -1) {
        alert("You didn't choose category !!!");

        return false;
    }
}

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