在JavaScript中设置变量的值
[英]Setting the value of a variable in JavaScript
问题描述
As you can see in the following code I'm fetching data from the MySQL database, but I got stuck when I wanted to use fetched "location" to set the "position" of a marker on a google map. 
如您在以下代码中看到的那样，我正在从MySQL数据库中获取数据，但是当我想使用获取的“位置”来设置Google地图上标记的“位置”时，我陷入了困境。
<head>
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=xxxxxxxxxxxxxxxxxxxxx&sensor=true"></script>
<script>
$.getJSON('http://www.wawhost.com/appProject/fetchmarker.php?callback=?', function(data) {
for (var i = 0; i < data.length; i++) {
localStorage.loc = data[i].location;
}
});
</script>
<script>
function initialize() {
var myLatlng = new google.maps.LatLng(-25.363882, 131.044922);
var mapOptions = {
zoom: 4,
center: myLatlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
var map = new google.maps.Map(document.getElementById('map_canvas'), mapOptions);
var marker = new google.maps.Marker({
position: 'new google.maps.LatLng(' + localStorage.loc + ')',
map: map,
title: 'Hello World!'
});
}
</script>
</head>
<body onload="initialize()">
<div id="map_canvas"></div>
</body>
Thank you! 谢谢！
1 个解决方案
解决方案1
1 已采纳 2013-01-10 03:32:47
Make the request when the page has loaded, and call the initialize function from the AJAX success callback. 页面加载后发出请求，并从AJAX成功回调中调用initialize函数。
$(function() {
$.getJSON('http://www.wawhost.com/appProject/fetchmarker.php?callback=?', function(data) {
for (var i = 0; i < data.length; i++) {
localStorage.loc = data[i].location;
}
initialize();
});
});
Also, this line looks a bit sketchy. 另外，这条线看起来有些粗略。 position is supposed to be a new google.maps.LatLng . position应该是新的google.maps.LatLng 。
position: 'new google.maps.LatLng(' + localStorage.loc + ')'.
LatLng takes an latitude and longitude argument to construct the object. LatLng采用纬度和经度参数来构造对象。 What you've stored from the request is a string , with comma seperated lat and long values. 您从请求中存储的是一个字符串 ，带有逗号分隔的lat和long值。
// First split the string into lat and long.
var pos = localStorage.loc.split(",");
// Parse the strings into floats.
var lat = parseFloat(pos[0]);
var lng = parseFloat(pos[1]);
// Create a new marker with the values from the request.
var marker = new google.maps.Marker({
position: new google.maps.LatLng(lat, lng),
map: map,
title: 'Hello World!'
});
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