[JavaScript] Get values from URL parameter
The following code will get the query parameters of a URL and assign them to an object called QueryMap.
// This function is anonymous, is executed immediately and the return value is assigned to QueryMap.
var QueryMap = function () {
var query_map = {};
//The search property sets or returns the querystring part of a URL, including the question mark (?).
//So we remove the question mark by removing the first characted of the string.
var query = window.location.search.substring(1);
var variables = query.split('&');
for (var i = 0; i < variables.length; i++) {
var position = variables[i].indexOf('=');
var key = variables[i].substring(0, position);
var value = variables[i].substring(position + 1);
// If it is the first entry with this name
if (typeof query_map[key] === "undefined") {
query_map[key] = decodeURIComponent(value);
// If it is the second entry with this name we change the value to an array of values
}
// If it is the second entry with this name we change the value to an array of values
else if (typeof query_map[key] === "string") {
var array = [query_map[key], decodeURIComponent(value)];
query_map[key] = array;
}
// If it is the third or later entry with this name we just add to the array
else {
query_map[key].push(decodeURIComponent(value));
}
}
return query_map;
}();
This code will handle cases where the equals sing (=) is part of the value of a variable.
Examples:
If the URL is http://example.com?a=1
Then QueryMap.a will contain value “1”.
If the URL is http://example.com?a=1&b=2
Then QueryMap.a will contain value “1” and QueryMap.b will contain value “2”.
If the URL is http://example.com?a=1=0001&b=2
Then QueryMap.a will contain value “1=0001” and QueryMap.b will contain value “2”.
If the URL is http://example.com?a=1=0001&b=2&b=0010
Then QueryMap.a will contain value “1=0001” and QueryMap.b will contain an array with the values “2” and “0010”.
