在onload事件中使用Javascript添加两个数字
[英]Add two numbers using Javascript on onload event
问题描述
How can i add two numbers from text box when the page loads? 
页面加载后，如何从文本框中添加两个数字？ it only works when i try to create a button for adding. 它仅在我尝试创建要添加的按钮时有效。
function sum() { var txtFirstNumberValue = document.getElementById('totalprice').value; var txtSecondNumberValue = document.getElementById('price1').value; var result = parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue); if (!isNaN(result)) { document.getElementById('totalprices').value = result; } }
3 个解决方案
解决方案1
1
use window.onload 使用window.onload
<script>
function sum() {
var txtFirstNumberValue = document.getElementById('totalprice').value;
var txtSecondNumberValue = document.getElementById('price1').value;
var result = parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('totalprices').value = result;
}
}
window.onload=sum;
</script>
解决方案2
1 2015-06-26 07:31:56
You either need to call the function when your document has finished loading with the window.onload listener https://developer.mozilla.org/en/docs/Web/API/GlobalEventHandlers/onload 当您使用window.onload侦听器完成文档加载后，您要么需要调用该函数window.onload侦听器https://developer.mozilla.org/en/docs/Web/API/GlobalEventHandlers/onload
ie 即
function sum(){
var txtFirstNumberValue = document.getElementById('totalprice').value;
var txtSecondNumberValue = document.getElementById('price1').value;
var result = parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('totalprices').value = result;
}
}
window.onload = sum;
Alternatively, you can run the code after the HTML in the document and without it being in a function and then it will interpret immediately 或者，您可以在文档中的HTML之后运行代码，而无需将其包含在函数中，然后它将立即解释
eg 例如
<html>
<div>some stuff here</div>
... // bottom of document
<script>
var txtFirstNumberValue = document.getElementById('totalprice').value;
var txtSecondNumberValue = document.getElementById('price1').value;
var result = parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('totalprices').value = result;
}
</script>
</html>
解决方案3
1 2015-06-26 07:34:58
If you prefer jQuery over regular Javascript: 如果您更喜欢jQuery，而不是常规Javascript：
$(document).ready(function() {
var txtFirstNumberValue = $('#totalprice').val();
var txtSecondNumberValue = $('#price1').val();
var result = (parseInt(txtFirstNumberValue) * parseInt(txtSecondNumberValue));
if (!isNaN(result)) {
$('#totalprices').val(result);
}
});
This will also fire sooner than a window.onload , resulting in a better user experience. 这也会比window.onload更快地触发，从而带来更好的用户体验。
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