<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>CSS-DOM</title> <link rel="stylesheet" type="text/css" href="10.css" > <script src="10.js"></script> </head> <body> <p id="message"> Whee! </p> </body> </html>
function positionMessage(){
if(!document.getElementById) return false;
if(!document.getElementById("message")) return false;
var elem = document.getElementById("message");
elem.style.position = "absolute";
elem.style.left = "50px";
elem.style.top ="100px";
moveElement("message",200,100,10);
}
function moveElement(elementID,final_x,final_y,interval){
if(!document.getElementById) return false;
if(!document.getElementById(elementID)) return false;
var elem = document.getElementById(elementID);
var xpos = parseInt(elem.style.left); //parseInt(string)把字符串里面的数值信息提取出来，因为后面要进行很多算术比较操作。
var ypos = parseInt(elem.style.top); //parseFloat(string)可以把带小数的数值（也就是浮点数）提取出来。
if(xpos == final_x && ypos == final_y){
return true;
}
if(xpos < final_x){ xpos++;} //如果xpos小于终点的left,给它加1.
if(xpos > final_x){ xpos--;} //如果xpos大于终点的left,给它减1.
if(ypos < final_y){ ypos++;} //如果ypos小于终点的left,给它加1.
if(ypos > final_y){ ypos--;} //如果ypos大于终点的left,给它减1.
elem.style.left = xpos + "px";
elem.style.top = ypos + "px";
//var repeat = function() {moveElement(elementID, final_x,final_y,interval)}
var repeat = "moveElement(‘" + elementID + "‘," + final_x + "," + final_y + "," + interval + ")";
movement = setTimeout(repeat,interval);
//clearTimeout(movement); 在等待的interval那时间内，可以取消这一“跳跃”行为
}
addLoadEvent(positionMessage);
时间： 2024-12-27 22:53:09