超简易脚本加载

load.js

// 简易ajax
function ajax(options) {
	var xhr = new XMLHttpRequest();

	xhr.open(options.type, options.url, true);

	xhr.send(options.data || '');

	xhr.onreadystatechange = function() {
		if(xhr.readyState === 4 && xhr.status === 200) {
			(function(data) {
				if(typeof options.success == 'function') {
					options.success(data);
				} else {
					console.log(data);
				}
			})(xhr.responseText);
		}
	};
}

// 获取本地存储
function load(item) {
	if(window['localStorage'] && window['localStorage']['getItem']) {
		return localStorage.getItem(item);
	}
}

// 本地存储
function save(item, value) {
	if(window['localStorage'] && window['localStorage']['setItem']) {
		localStorage.setItem(item, value);
	}
}

// 获取本地脚本
function loadScript(files) {
	for(var i = 0, flen = files.length; i < flen; ++i) {
		var a = document.createElement('a');
		a.href = files[i];
		files[i] = a.pathname;
	}

	var newScript = new ScriptRuntime(files);

	var fileUrl = '';
	for(var i = 0, flen = files.length; i < flen; ++i) {
		fileUrl = files[i];
		if(fileUrl.length == 0) continue;
		value = load(fileUrl);
		if(!value) {
			(function(index, url){
				ajax({
					type: 'GET',
					url: url,
					success: function(data) {
						save(url, data);
						newScript.add(url, data);
						console.log('[AJAX][SIZE:' + data.length + '] "' + fileUrl + '"');
					}
				})
			})(i, fileUrl);
		} else {
			newScript.add(fileUrl, value);
			console.log('[CACHE][SIZE:' + value.length + '] "' + fileUrl + '"');
		}
	}
}

function ScriptRuntime(dependences, tailFunction) {
	this.dependences = [];
	this.indexs = {};
	this.loadedCount = 0;

	for(var i = 0, dlen = dependences.length; i < dlen; ++i) {
		if(dependences[i].length > 0) {
			this.dependences.push({
				'name': dependences[i],
				'code': '',
				'loaded': false
			});
			this.indexs[dependences[i]] = i;
		}
	}

	this.add = function(name, data) {
		var index = this.indexs[name];
		if(typeof index == 'number') {
			this.dependences[index].code = data;
			this.dependences[index].loaded = true;
			this.loadedCount += 1;

			if(this.loadedCount == this.dependences.length) {
				var allCode = '';
				for(var i = 0, len = this.dependences.length; i < len; ++i) {
					allCode = allCode + this.dependences[i].code + ';\n';
				}

				(new Function(allCode))();
			}
		}
	}
}


// 用法示例
window.onload = function() {
    loadScript(['test1.js', 'test2.js']);
}