解决方法
如果是相同的域请求,则使用window.XMLHttpRequest.如果它是远程的,然后注入一个脚本元素,你可以看到jQuery如何做到：
// If we're requesting a remote document
// and trying to load JSON or Script with a GET
if ( s.dataType === "script" && type === "GET" && remote ) {
var head = document.getElementsByTagName("head")[0] || document.documentElement;
var script = document.createElement("script");
script.src = s.url;
if ( s.scriptCharset ) {
script.charset = s.scriptCharset;
}
// Handle Script loading
if ( !jsonp ) {
var done = false;
// Attach handlers for all browsers
script.onload = script.onreadystatechange = function() {
if ( !done && (!this.readyState ||
this.readyState === "loaded" || this.readyState === "complete") ) {
done = true;
success();
complete();
// Handle memory leak in IE
script.onload = script.onreadystatechange = null;
if ( head && script.parentNode ) {
head.removeChild( script );
}
}
};
}
// Use insertBefore instead of appendChild to circumvent an IE6 bug.
// This arises when a base node is used (#2709 and #4378).
head.insertBefore( script,head.firstChild );
// We handle everything using the script element injection
return undefined;
}
使用一个JSON Parser.你也可以使用eval,但它是一个赞成JSON解析器的皱眉头.
这是jQuery的内部parseJSON方法：
parseJSON: function( data ) {
if ( typeof data !== "string" || !data ) {
return null;
}
// Make sure leading/trailing whitespace is removed (IE can't handle it)
data = jQuery.trim( data );
// Make sure the incoming data is actual JSON
// Logic borrowed from http://json.org/json2.js
if ( /^[\],:{}\s]*$/.test(data.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g,"@")
.replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g,"]")
.replace(/(?:^|:|,)(?:\s*\[)+/g,"")) ) {
// Try to use the native JSON parser first
return window.JSON && window.JSON.parse ?
window.JSON.parse( data ) :
(new Function("return " + data))();
} else {
jQuery.error( "Invalid JSON: " + data );
}
},
