勘误版
    function getQuery( key , url )
    {
        url = url || window.location.href;
        if ( url.indexOf( '#' ) !== -1 )
            url = url.substring( 0 , url.indexOf( '#' ) );
        var rts = [],rt;
        var queryReg = new RegExp( '(^|\\?|&)' + key + '=([^&]*)(?=&|$|#)' , 'g' );
        while ( ( rt = queryReg.exec( url ) ) != null )
        {
            rts.push( decodeURIComponent( rt[ 2 ] ) );
        }
        if ( rts.length == 0 ) return null;
        if ( rts.length == 1 ) return rts[ 0 ];
        return rts;
    }
    

    function setQuery( key , value , url )
    {
        
        url = url || window.location.href;
        var hash = '';

        if ( url.indexOf( '#' ) !== -1 )
            hash = url.substring( url.indexOf( '#' ) );
        
        url = url.replace( hash , '' );
        url = url.replace( new RegExp( '(^|\\?|&)' + key + '=[^&]*(?=&|#|$)' , 'g' ) , '' );
        value = isArray( value ) ? value : [ value ];
        
        for ( var i = value.length - 1;i >= 0;i --)
        {
            value[ i ] = encodeURIComponent( value[ i ] );
        }

        var p = key + '=' + value.join( '&' + key + '=' );
        return url + ( /\?/.test( url ) ? '&' : '?' ) + p + hash;
    }
增强版,支持同名参数
    function getQuery( key , url )
    {
        url = url || window.location.href;
        var rts = [],rt;
        var queryReg = new RegExp( '(^|\\?|&)' + key + '=([^&]*)(?=&|$|#)' , 'g' );
        while ( ( rt = queryReg.exec( url ) ) != null )
        {
            rts.push( decodeURIComponent( rt[ 2 ] ) );
        }
        if ( rts.length == 0 ) return null;
        if ( rts.length == 1 ) return rts[ 0 ];
        return rts;
    }
    

    function setQuery( key , value , url )
    {
        
        url = url || window.location.href;
        url = url.replace( new RegExp( '(^|\\?|&)' + key + '=[^&]*(?=&|$|#)' , 'g' ) , '' );
        value = value.splice ? value : [ value ];
        
        for ( var i = value.length - 1;i >= 0;i --)
        {
            value[ i ] = encodeURIComponent( value[ i ] );
        }

        var p = key + '=' + value.join( '&' + key + '=' );
        return url + ( /\?/.test( url ) ? '&' : '?' ) + p;
    }
虽然正则用的不怎么样,但还是偷懒首选~
	function getQuery( key , url ) {
		var reg = new RegExp( '^\\S*(\\?|&)' + key + '=([^&]*)\\S*$' );
		var l = url || window.location.href;
		if ( reg.test( l ) ) {
			return decodeURIComponent( l.replace( reg , '$2' ) );
		} else {
			return null;
		}
	}
	
	function setQuery( key , value , url ) {
		var reg = new RegExp( key + '=[^&]*(?=&|$)' );
		var l = url || window.location.href;
		if ( reg.test( l ) ) {
			return l.replace( reg , key + '=' + encodeURIComponent( value ) );
		}else{
			return l + ( /\?/.test( l ) ? '&' : '?' ) + key + '=' + encodeURIComponent( value );
		}
	}