生成随机id

[lynxerzhang]

//https://github.com/tejacques/crosstab 参考crosstab库中的实现
var generateId = (function(){
    var pad = function(num, width, paddingStr){
        paddingStr = paddingStr || "0";
        num = num.toString();
        if(num.length >= width){
            return num;
        }
        return new Array((width - num.length) + 1).join(paddingStr) + num;
    }
    var time = function() {
        return new Date().getTime();
    }
    return function(){
        return time().toString() + pad((Math.random() * 0x7FFFFFFF)|0, 10);
    }
})();

//example
var id = generateId(); //