用JS写的一个Ajax库(实例代码)

myajax.get({<span style="white-space:pre">	</span>data: {}, //参数	url: "", //请求地址	//发生错误是调用	error: function(data) {	},	//请求成功调用	success: function(data){		<span style="white-space:pre">	</span>//eval(data); 将字符串转换成json	}});

myajax.post({	data: {}, //参数	url: "", //	//发生错误是调用	error: function(data) {	},	//请求成功调用	success: function(data){	//eval(data); 将字符串转换成json	}});

myajax.getJSONP({//参数data: {},url: "", //请求地址//请求成功调用success: function(data) {},//发生错误时调用error: function() {}});

var myajax = {	post: function(params){		var xmlhttp = this.createXMLHttpRequest();		if (xmlhttp != null)		{			var async = true;			if (typeof params.async != "undefined")				async = params.async;			var data = null;			if (typeof params.data != "undefined")				data = params.data;			var url = "";			if (typeof params.url != "undefined")				url = params.url;			if (url == null || url.length == 0)				return;			xmlhttp.open("POST", url, async);			if (async){				xmlhttp.onreadystatechange = function(){									if (this.readyState==4){						if (this.status==200){							if (typeof params.success != "undefined") {								params.success(xmlhttp.responseText);							}						}						else {							if (typeof params.error != "undefined") {								params.error(xmlhttp.status + xmlhttp.statusText);							}							console.error(url + ": " + xmlhttp.status);						}					}				};			}						xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");			var param = "";			for (var prop in data) {				param += prop + "=" + data[prop] + "&";			}			param = param.substring(0, param.length - 1);			xmlhttp.send(param);			if (!async) {								if (xmlhttp.readyState == 4 && xmlhttp.status == 200)							if (typeof params.success != "undefined") {						params.success(xmlhttp.responseText);					}				else {					if (typeof params.error != "undefined") {						params.error(xmlhttp.status + xmlhttp.statusText);					}					console.error(url + ": " + xmlhttp.status);				}							}		}	},	get: function(params){		var xmlhttp = this.createXMLHttpRequest();		if (xmlhttp != null)		{			var async = true;			if (params.async != undefined)				async = params.async;			var url = "";			if (params.url != undefined)				url = params.url;			if (url == null || url.length == 0)				return;			if (params.data != null) {				var data = params.data;				var paramPrefix = url.indexOf("?") == -1 ? "?" : "&";						url = url + paramPrefix;				for (var prop in data) {					url += prop + "=" + data[prop] + "&";				}				url = url.substring(0, url.length - 1);			}			xmlhttp.open("GET", url, async);			if (async){				xmlhttp.onreadystatechange = function(){					if (this.readyState==4){						if (this.status==200){							if (typeof params.success != "undefined") {								params.success(xmlhttp.responseText);							}						}						else {							if (typeof params.error != "undefined") {								params.error(xmlhttp.status + xmlhttp.statusText);							}							console.error(url + ": " + xmlhttp.status);						}					}				};			}			xmlhttp.send(null);			if (!async) {				if (xmlhttp.readyState == 4 && xmlhttp.status == 200)					if (typeof params.success != "undefined") {						params.success(xmlhttp.responseText);					}				else {					if (typeof params.error != "undefined") {						params.error(xmlhttp.status + xmlhttp.statusText);					}					console.error(url + ": " + xmlhttp.status);				}													}		}	},	createXMLHttpRequest: function(){		if (window.XMLHttpRequest)		{			return new XMLHttpRequest();		}		else if (window.ActiveXObject)		{		//code for IE5 and IE6			return new ActiveXObject("Microsoft.XMLHTTP");		}		return null;	},	getJSONP: function(params) {		var url = null;		if (typeof params.url != "undefined") {			url = params.url;		}		if (url == null) {			return;		}				var ff = "" + new Date().getTime() + (parseInt(Math.random() * 10000000000));		eval("jsonpCallback_" + ff + "=" + function(data){				if (typeof params.success != "undefined") {				params.success(data);			}		});		//根据url中是否出现过 "?" 来决定添加时间戳参数时使用 "?" 还是 "&" 		var paramPrefix = url.indexOf("?") == -1 ? "?" : "&";		url = url + paramPrefix + "jsonpCallback=" + "jsonpCallback_" + ff;		var param = "";		if (typeof params.data != "undefined" && params.data != null) {					var data = params.data;			for (var prop in data) {				param += prop + "=" + data[prop] + "&";			}			param = param.substring(0, param.length - 1);		}		if (param.length > 0)		url = url + "&" + param; 		var script = document.createElement("script"); 		document.body.appendChild(script); 		script.src = url; 		script.charset ="UTF-8";		// for firefox, google etc.		script.onerror = function() {			if (typeof params.error != "undefined") {				params.error();			}				 	}		script.onload = function() {		document.body.removeChild(script); 		} 		// for ie 		script.onreadystatechange = function() { 		  if (this.readyState == "loaded" || this.readyState == "complete") { 		    document.body.removeChild(script);		  } 		}	}};