js 获取上传图片的宽高

document.getElementById('fileInput').addEventListener('change', function(event) {
    var file = event.target.files[0];
    if (file) {
        var reader = new FileReader();
        reader.onload = function(e) {
            var img = new Image();
            img.onload = function() {
                console.log('宽度: ' + this.width);
                console.log('高度: ' + this.height);
            };
            img.src = e.target.result;
        };
        reader.readAsDataURL(file);
    }
});

document.getElementById('fileInput').addEventListener('change', function(event) {
    var file = event.target.files[0];
    if (file) {
        var imgURL = URL.createObjectURL(file);
        var img = new Image();
        img.onload = function() {
            console.log('宽度: ' + this.width);
            console.log('高度: ' + this.height);
            URL.revokeObjectURL(imgURL); // 释放内存
        };
        img.src = imgURL;
    }
});

document.getElementById('fileInput').addEventListener('change', function(event) {
    var file = event.target.files[0];
    if (file) {
        var reader = new FileReader();
        reader.onload = function(e) {
            var img = new Image();
            img.onload = function() {
                var canvas = document.createElement('canvas');
                canvas.width = this.width;
                canvas.height = this.height;
                var ctx = canvas.getContext('2d');
                ctx.drawImage(this, 0, 0);
                // 如果需要，可以从canvas获取图片数据
                URL.revokeObjectURL(img.src); // 释放内存
            };
            img.src = e.target.result;
        };
        reader.readAsDataURL(file);
    }
});