[英]FOR loop to iterate through array
我有一个数组,我想使用for loop
进行迭代,以避免过多的代码。 我想采取以下几点:
var mySchool = document.getElementById(varID[0]);
google.maps.event.addDomListener(mySchool,'click', function() {
filterMap(layer, tableId, map);
});
并使其更像是:
for(var i=0; i < varID.length; i++){
var mySchool = document.getElementById(varID[i]);
google.maps.event.addDomListener(mySchool,'click', function() {
filterMap(layer, tableId, map);
});
}
我一直在读一些书,我怀疑它与Javascript闭包有关,但是我一生都无法使其与我发现的各种代码示例一起使用。 我希望有经验的眼睛能发现我在Javascript新手中缺少的东西。
我完整的代码如下:
//There are more items in my array but i wanted to keep it short here
var varID = [
"adamRobertson",
"blewett",
"brentKennedy"
];
var tableId = '1yc4wo1kBGNJwpDm6e-eJY_KL1YhQWfftjhA38w8';
function initialize() {
var map = new google.maps.Map(document.getElementById('map-canvas'), {
center: new google.maps.LatLng(49.491052,-117.304484),
zoom: 10,
mapTypeId: google.maps.MapTypeId.ROADMAP
});
var layer = new google.maps.FusionTablesLayer();
filterMap(layer, tableId, map);
//Trying to get this to work
for(var i=0; i < varID.length; i++){
var mySchool = document.getElementById(varID[i]);
google.maps.event.addDomListener(mySchool,'click', function() {
filterMap(layer, tableId, map);
});
}
//Trying to avoid this 25 times
/*
google.maps.event.addDomListener(document.getElementById(varID[0]),
'click', function() {
filterMap(layer, tableId, map);
});
*/
}
// Filter the map based on checkbox selection.
function filterMap(layer, tableId, map) {
var where = generateWhere();
if (where) {
if (!layer.getMap()) {
layer.setMap(map);
}
layer.setOptions({
query: {
select: 'Location',
from: tableId,
where: where
}
});
} else {
layer.setMap(null);
}
}
// Generate a where clause from the checkboxes. If no boxes
// are checked, return an empty string.
function generateWhere() {
var filter = [];
var schools = document.getElementsByName('school');
for (var i = 0, school; school = schools[i]; i++) {
if (school.checked) {
var schoolName = school.value.replace(/'/g, '\\\'');
filter.push("'" + schoolName + "'");
}
}
var where = '';
if (filter.length) {
where = "School IN (" + filter.join(',') + ')';
}
return where;
}
google.maps.event.addDomListener(window, 'load', initialize);
HTML基本上包含复选框的输入,以打开或关闭我的多边形。
在此先感谢您的帮助。
我认为如果将代码更改为此:
var mySchool; var limit = varID.length;
for(var i=0; i < limit; i++){
mySchool = document.getElementById(varID[i]);
(function(){
google.maps.event.addDomListener(mySchool,'click', function() {
filterMap(layer, tableId, map);
});
}());
}
我将for极限计算从循环中取出,这样也可以节省一些速度。
我没有使用过maps api,因此您可能必须在闭包中添加一些参数。
var mySchool; var limit = varID.length;
for(var i=0; i < limit; i++){
mySchool = document.getElementById(varID[i]);
(function(s, l, t, m){
google.maps.event.addDomListener(s,'click', function() {
filterMap(l, t, m);
});
}(mySchool, layer, tableId, map));
}
我不确定需要哪些args,但是您可能会发现。
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