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  • js笔记---拖动元素

    <!DOCTYPE html>
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title></title>
        <style>
            #img1 { position: absolute; }
        </style>
        <script type="text/javascript">
            window.onload = function () {
                var oImg = document.getElementById('img1');
                drop(oImg);
            }
            function drop(obj) {
                obj.onmousedown = function (ev) {
                    var ev = ev || event;
                    var liw = ev.clientX - parseInt(getStyle(obj, 'left') == 'auto' ? '0' : getStyle(obj, 'left'));
                    var lit = ev.clientY - parseInt(getStyle(obj, 'top') == 'auto' ? '0' : getStyle(obj, 'top'));
                    if (obj.getCaptrue) {
                        obj.getCaptrue();
                    }
                    document.onmousemove = function (ev) {
                        var ev = ev || event;
                        var L = ev.clientX - liw;
                        var T = ev.clientY - lit;
                        if (L < 100) {
                            L = 0;
                        }
                        if (L > document.documentElement.clientWidth - obj.offsetWidth-100) {
                            L = (document.documentElement.clientWidth - obj.offsetWidth);
                        }
                        if (T < 100) {
                            T = 0;
                        }
                        if (T > document.documentElement.clientHeight - obj.offsetHeight - 100) {
                            T = (document.documentElement.clientHeight - obj.offsetHeight);
                        }
                        obj.style.left = L + 'px';
                        obj.style.top = T + 'px';
                    }
                    document.onmouseup = function () {
                        document.onmousemove = document.onmouseup = null;
                        if (obj.relaseCaptrue) {
                            obj.relaseCaptrue();
                        }
                    }
                    return false;
                }
            }
            function getStyle(obj, attr) {
                if (obj.currentStyle) {
                    return obj.currentStyle[attr];
                } else {
                    return getComputedStyle(obj, false)[attr];
                }
            }
        </script>
    </head>
    <body>
        <img src="images/btn_04.jpg" id="img1" />
        <!--<img src="images/btn_02.jpg" />-->
    </body>
    </html>
    

      

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  • 原文地址:https://www.cnblogs.com/juexin/p/4067279.html
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