Javascript retrieves an instance of url parameters

Today, a friend asked the webmaster about how to obtain the url parameter value. In webpage design, sometimes we need to obtain the Link parameter on the client, A common method is to use a link as a string, break it down according to the link format, and then obtain the corresponding parameter value. The fire shows the specific implementation of this process.

Of course, we can also use regular expressions for direct matching. This article also provides an example of regular expressions.

Link decomposition method:

<Script type = "text/javascript">
<! --
// Description: Javascript method for obtaining url parameters
// Finishing: http://www.bkjia.com

Function getQueryString (name)
{
// If the link does not have a parameter or the link does not contain the parameter we want to obtain, a blank result is returned.
If (location. href. indexOf ("? ") =-1 | location. href. indexOf (name + '=') =-1)
{
Return '';
}

// Obtain the parameters in the Link
Var queryString = location. href. substring (location. href. indexOf ("? ") + 1 );

// What are the separation parameter pairs? Key = value & key2 = value2
Var parameters = queryString. split ("&");

Var pos, paraName, paraValue;
For (var I = 0; I <parameters. length; I ++)
{
// Obtain the equal sign position
Pos = parameters [I]. indexOf ('= ');
If (pos =-1) {continue ;}

// Obtain the name and value
ParaName = parameters [I]. substring (0, pos );
ParaValue = parameters [I]. substring (pos + 1 );

// If the query name is equal to the current name, the current value is returned. At the same time, the + sign in the link is restored to a space.
If (paraName = name)
{
Return unescape (paraValue. replace (// ++/g ,""));
}
}
Return '';
};

// Http: // localhost/test.html? Aa = bb & test = cc + dd & ee = ff
Alert (getQueryString ('test '));
// -->
</Script>

Regular Expression matching:

<Script type = "text/javascript">
<! --
Function getQueryStringRegExp (name)
{
Var reg = new RegExp ("(^ | \\? | &) "+ Name +" = ([^ &] *) (\ s | & | $) "," I ");
If (reg. test (location. href) return unescape (RegExp. $2. replace (/\ +/g, ""); return "";
};

// Http: // localhost/test.html? Aa = bb & test = cc + dd & ee = ff
Alert (getQueryStringRegExp ('test '));
// -->
</Script>