我正在学习坚固性（对于智能合约），现在需要设计一个UI来与部署合同进行交互。
注意：如果问题与此论坛无关，请让我知道（而不是退票），我将删除它。
我的html和.js文件如下。问题在于，当我同时包含" distribute（）"one_answers" update_exchange_rate（）"功能中时，我的html文件将不起作用。但是如果我从.js文件中删除它们。
我不会有任何问题。问题：我为什么遇到这个问题？如何解决上述问题？我可以在window.app中具有多个函数（定义）吗？
编辑：如果我将两个函数都放在.js文件中，我也会收到WebPack错误。但是，如果我删除其中一个功能，则错误将消失。
<!DOCTYPE html>
<html>
<head>
<script src="./app.js"></script>
</head>
<body>
<h1>MetaCoin</h1>
<h2>Example Truffle Dapp</h2>
<br>
<br><label for="amountB">Exchange rate:</label><input type="text"
id="amountA" placeholder="e.g., 95"></input>
<br><label for="receiverA">ReceiverA:</label><input type="text"
id="receiverA" placeholder="e.g., 95"></input>
<br><label for="receiverB">ReceiverB:</label><input type="text"
id="receiverB" placeholder="e.g., 95"></input>
<br><br><button id="send1" onclick="App.distribute()">Send
MetaCoin</button>
<br><br>
<br><label for="amountB">Exchange rate:</label><input type="text"
id="amountB" placeholder="e.g., 95"></input>
<br><br><button id="send2"
onclick="App.update_exchange_Rate()">update_exchange_Rate</button>
<br><br>
<br>
</body>
</html>
我的JS文件是：
import "../stylesheets/app.css";
import { default as Web3} from 'web3';
import { default as contract } from 'truffle-contract'
import metacoin_artifacts from '../../build/contracts/MetaCo.json'
var MetaCo = contract(metacoin_artifacts);
var accounts;
var account;
window.App = {
start: function() {
MetaCo.setProvider(web3.currentProvider);
web3.eth.getAccounts(function(err, accs) {
if (err != null) {
alert("There was an error fetching your accounts.");
return;
}
if (accs.length == 0) {
alert("Couldn't get any accounts! Make sure your Ethereum client is
configured correctly.");
return;
}
accounts = accs;
account = accounts[0];
});
},
setStatus: function(message) {
var status = document.getElementById("status");
status.innerHTML = message;
},
distribute: function() { // XXX Here is where the problem occures!
var amountA = parseInt(document.getElementById("amountA").value);
var receiver1= document.getElementById("receiverA").value;
var receiver2 = document.getElementById("receiverB").value;
var meta;
MetaCo.deployed().then(function(instance2) {
meta = instance2;
return meta.distribute(receiver1,receiver2, amountA,{from: account});
})
}
update_exchange_Rate: function() { // XXX Here is where the problem occures!
var amountB = parseInt(document.getElementById("amountB").value);
var meta1;
MetaCo.deployed().then(function(instance3) {
meta1 = instance3;
return meta1.update_exchange_Rate(amountB,{from: account});
})
}
};
window.addEventListener('load', function() {
if (typeof web3 !== 'undefined') {
console.warn("Using web3 detected from external source. If you find
that your accounts don't appear or you have 0 MetaCoin, ensure you've
configured that source properly. If using MetaMask, see the following
link.
Feel free to delete this warning. :)
http://truffleframework.com/tutorials/truffle-and-metamask")
// Use Mist/MetaMask's provider
window.web3 = new Web3(web3.currentProvider);
} else {
console.warn("No web3 detected. Falling back to http://localhost:8545.
You should remove this fallback when you deploy live, as it's
inherently
insecure. Consider switching to Metamask for development. More info
here:
http://truffleframework.com/tutorials/truffle-and-metamask");
// fallback - use your fallback strategy (local node / hosted node +
in-dapp id mgmt / fail)
window.web3 = new Web3(new
Web3.providers.HttpProvider("http://localhost:8545"));
}
App.start();
});
让我们只按照此按钮，另一个按钮有完全相同的问题...
<button id="send2" onclick="App.update_exchange_Rate()">update_exchange_Rate</button>
ONCLICK属性期望接收功能。然后，每次点击都会调用该功能。但是该函数不会返回函数本身...
app.update_exchange_rate（）将在浏览器看到该部分后立即执行，并且使用的返回值使用。但这不是我们想要的！我们希望执行该功能...因此我们需要提供该功能，而不是对属性的调用，例如：
<button id="send2" onclick="App.update_exchange_Rate">update_exchange_Rate</button>
或
<button id="send2" onclick="function(){App.update_exchange_Rate();}">update_exchange_Rate</button>
现在，如果您这样做，您肯定会遇到您没有想到的范围。您在功能中没有使用this，所以我会跳过该范围的部分，如果需要，您可以稍后阅读。