javascript函数节流（throttle）与函数去抖（debounce）

function throttle(fn, threshhold, scope) { 
    threshhold || (threshhold = 250); 
    var last, timer; 
    return function () {
        var context = scope || this; 
        var now = +new Date(), 
            args = arguments; 
        if (last && now - last + threshhold < 0) { 
            // hold on to it 
            clearTimeout(deferTimer); 
            timer = setTimeout(function () { 
                last = now; 
                fn.apply(context, args); 
            }, threshhold); 
        } else { 
            last = now; 
            fn.apply(context, args); 
        } 
    };
}

//调用方法
$(‘body‘).on(‘mousemove‘, throttle(function (event) {
    console.log(‘tick‘);
}, 1000));

function debounce(fn, delay) { 
    var timer = null; 
    return function () { 
        var context = this,
        args = arguments; 
        clearTimeout(timer); 
        timer = setTimeout(function () { 
            fn.apply(context, args); 
        }, delay); 
    };
}

//调用方法
$(‘input.username‘).keypress(debounce(function (event) {
// do the Ajax request
}, 250));