jquery工具方法parseJSON

error : 自定义错误

parseJSON : 字符串转json

trim : 去除字符串头尾空字符

parseJSON方法先判断参数是否为字符串，否则返回空对象，再去除字符串头尾空字符，判断是否支持window.JSON.parse，否则使用json2.js中的方法。

var core_trim = String.prototype.trim,
    // Make sure we trim BOM and NBSP (here's looking at you, Safari 5.0 and IE)
    rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g,
    // JSON RegExp
    rvalidchars = /^[\],:{}\s]*$/,
    rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g,
    rvalidescape = /\\(?:["\\\/bfnrt]|u[\da-fA-F]{4})/g,
    rvalidtokens = /"[^"\\\r\n]*"|true|false|null|-?(?:\d\d*\.|)\d+(?:[eE][\-+]?\d+|)/g;

jQuery.extend({

    ......................

    error: function( msg ) {
        throw new Error( msg );
    },

    parseJSON: function( data ) {
        if ( !data || typeof data !== "string") {
            return null;
        }

        // Make sure leading/trailing whitespace is removed (IE can't handle it)
        data = jQuery.trim( data );

        // Attempt to parse using the native JSON parser first
        if ( window.JSON && window.JSON.parse ) {
            return window.JSON.parse( data );
        }

        // Make sure the incoming data is actual JSON
        // Logic borrowed from http://json.org/json2.js
        if ( rvalidchars.test( data.replace( rvalidescape, "@" )
            .replace( rvalidtokens, "]" )
            .replace( rvalidbraces, "")) ) {

            return ( new Function( "return " + data ) )();

        }
        jQuery.error( "Invalid JSON: " + data );
    },

    // Use native String.trim function wherever possible
    trim: core_trim && !core_trim.call("\uFEFF\xA0") ?
        function( text ) {
            return text == null ?
                "" :
                core_trim.call( text );
        } :

        // Otherwise use our own trimming functionality
        function( text ) {
            return text == null ?
                "" :
                ( text + "" ).replace( rtrim, "" );
        },

    ...............

});