how to get value from a html using external javascript
Question
I have two javascript files, js1 and js2. js1 is defined in index.jsp. and inside js1 i'm using js2. once i'm executing js2 i want to take some values from index.jsp. (js2 can't define in ndex.jsp file) so, How can i access html using this external js file (js2)
this is my index.jsp
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<script type="text/javascript" src="js1.js"></script>
</head>
<body>
<h1>test</h1>
<span id="up"></span>test<br><br><span id="down"></span>
<br><br>
Time : <span id="foo"></span>
<br><br>
<div id="uid" >this is the value i want to access</div>
<button onclick="start()">Start sync</button>
</body>
this is js1.js
navigator.serviceWorker.register('js2.js', { scope: '/login/' }).then(function(reg) {
if(reg.installing) {
console.log('Service worker installing');
} else if(reg.waiting) {
console.log('Service worker installed');
} else if(reg.active) {
console.log('Service worker active');
}
//setTimeout(refresh, 10000);
}).catch(function(error){
console.log('Registration failed with ' + error);
});
this is js2.js
var eventSource2 = new EventSource("HelloServlet");
eventSource2.addEventListener('down_vote',function(event){
console.log("data from down" , event.data);
var MyDiv1 = document.getElementById('uid'); //this is not working
var val = MyDiv1.innerHTML; //this is not working
console.log(val + "ddddd 2"); //this is not working
console.log("down");
});
2 answers
solution1
0 2016-01-26 05:42:37
There is a mystery variable index
var MyDiv1 = index.getElementById('uid'); //this is not working
should probably be
var MyDiv1 = document.getElementById('uid');
solution2
0 2016-01-26 06:41:52
You are including js1.js at the beggining of you main page, so it can't find the DOM elements of index.jsp
You should include js1.js at the end of index.jsp
or include it in document.ready() of index.jsp
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>test</h1>
<span id="up"></span>test<br><br><span id="down"></span>
<br><br>
Time : <span id="foo"></span>
<br><br>
<div id="uid" >this is the value i want to access</div>
<button onclick="start()">Start sync</button>
<script type="text/javascript" src="js1.js"></script>
</body>
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