android4.4zepto.tap偶尔需点击两次bug分析

$(document)                                                                      
    .on('touchstart', function() {                                               
        // 打酱油                                                                
    })                                                                           
    .on('touchmove', function() {                                                
        deltaX += XXX;                                                           
        deltaY += XXX;                                                           
    })                                                                           
    .on('touchend', function() {                                                 
        if (deltaX < 30 && deltaY < 30) {                                                                                                                
            // you tap me                                                           
            touch.el && touch.el.trigger(event)                                     
        }                                                                           
        deltaX = deltaY = 0;                                                                                                                              
    })                                                                           
    .on('touchcancel', function() {                                                 
        // 打酱油                                                                   
    });

deltaX = deltaY = 0;