//获取文件路径
function getObjectURL(file) { 
    var url = null
    if (window.createObjectURL != undefined) {  // basic 
        url = window.createObjectURL(file)
    } else if (window.URL != undefined) {  // mozilla(firefox) 
        url = window.URL.createObjectURL(file)
    } else if (window.webkitURL != undefined) {  // webkit or chrome 
        url = window.webkitURL.createObjectURL(file)
    }
    return url;
}

//使用：
var file = document.getElementById("file");
var realPath = getObjectURL(file.files[0]);