将JQuery ajax调用转换为原始Javascript-无法POST/public/错误 [英] Converting JQuery ajax call to vanilla Javascript - Cannot POST /public/ error
问题描述
So this is a slight follow up to a question I had yesterday (Update HTML input value in node.js without changing pages), I'm attempting to submit a HTML form, send an ajax request to my server which supplies two numbers, these numbers are added on the server and then shown in a box on the same HTML page as the form. So far I received a solution in JQuery which was extremely useful, however my manager wants it done in javascript for various reasons. I've had a go so far, but as many people use JQuery for this, examples of a vanilla javascript method are few and far between. At present, on submission a page is thrown saying "Cannot POST /public/", I'm new to ajax so I'm reasonably sure the problem lies there.
我的(有效的)JQuery代码:
My (working) JQuery code:
$(document).ready(function(){
$("#add").submit(function(event){
event.preventDefault();
var num1 = $("#numa").val();
var num2 = $("#numb").val();
$.ajax({
method: "post",
url: '/add',
data: JSON.stringify({ num1: num1, num2: num2 }),
contentType: 'application/json',
success: function(data){
$("#answer").val(data);
}
})
})
})
我尝试转换为javascript:
My attempt at converting to javascript:
function add(){
var xml = new XMLHttpRequest();
var num1 = document.getElementById("numa");
var num2 = document.getElementById("numb");
xml.open("POST", "/add", true);
xml.setRequestHeader("Content-Type", "application/json");
xml.onreadystatechange = function(){
if(xml.readyState == XMLHttpRequest.DONE){
document.getElementById("answer").value = xml.responseText;
}
}
xml.send(JSON.stringify({num1: num1, num2: num2}));
}
我的app.js:
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var app = express();
app.set('port', process.env.PORT || 8080);
app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, '../static')));
app.get('/', function(req, res){
res.redirect('/public');
});
app.post('/add', function(req, res){
var a = parseFloat(req.body.num1);
var b = parseFloat(req.body.num2);
var sum = a+ b;
res.send(sum.toString());
});
var server = app.listen(app.get('port'), function(){
var port = server.address().port;
});
为完成我的HTML表单,
For completion, my HTML form:
<form id="add" method="post">
Number 1:
<input type="number" id="numa" name="numa" step="any"/><br>
Number 2:
<input type="number" id="numb" name="numb" step="any"/><br>
<input type="number" id="answer" name="answer" readonly/>
<input type="submit" value="Submit" onclick="add()"/>
</form>
任何指针都很好,谢谢!
Any pointers would be great, thanks!
推荐答案
除以下两行外,其他所有内容看起来都不错:
all looks good except the two lines:
var num1 = getElementById("numa");
var num2 = getElementById("numb");
应该是这样
var num1 = document.getElementById("numa");
var num2 = document.getElementById("numb");
注意:更新的html代码(在表单提交时添加了HTML代码,并已从按钮中删除)
<form id="add" method="post" onsubmit="return add()">
Number 1:
<input type="number" id="numa" name="numa" step="any"/><br>
Number 2:
<input type="number" id="numb" name="numb" step="any"/><br>
<input type="number" id="answer" name="answer" readonly/>
<input type="submit" value="Submit"/>
</form>
这篇关于将JQuery ajax调用转换为原始Javascript-无法POST/public/错误的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!