JavaScript碰壁反彈效果代碼

2024-09-05 12:20:58

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JavaScript碰壁反彈效果代碼，碰壁物體可設(shè)置大小，設(shè)置完成，點(diǎn)擊“開始”可看到運(yùn)動效果，當(dāng)物體的四邊或論是哪個(gè)邊碰到外框時(shí)，都會自動反彈，類似的效果被廣泛應(yīng)用于游戲開發(fā)中。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>碰壁反彈</title><style>       #text {width:500px;height:300px;border:10px red solid;margin:0 auto;position:relative;}       #div1 {width:50px;height:50px;border:5px yellow solid;position:absolute;}</style></head><body><div   class="70qarhlowxag"   id="text">       <div   class="70qarhlowxag"   id="div1"></div></div><input type="button" value="開始"/><input type="button" value="變大"/><input type="button" value="變小"/><input type="button" value="停止"/></body><script type="text/javascript">       var text = document.getElementById("text");       var div1 = document.getElementById("div1");       var a = div1.offsetTop;       var b = div1.offsetLeft;       var id = true;       var id2 = true;       var ss=null;       var qw = 50;       var ge = true;       var gg = true;       function pbft(){              var width = text.clientWidth;              var height = text.clientHeight;              var width2 = div1.offsetWidth;              var height2 = div1.offsetHeight;              var width3 = width - width2;              var height3 = height - height2;                                   if(id){                     if(b<width3){                            b++;                            this.div1.style.left = b + "px";                     }else{                            id = false;                     }              }else{                     if(b>0){                            b--;                            this.div1.style.left = b + "px";                     }else{                            id=true;                     }              }              if(id2){                     if(a<height3){                            a++;                            this.div1.style.top = a + "px";                     }else{                            id2 = false;                     }              }else{                     if(a>0){                            a--;                            this.div1.style.top = a + "px";                     }else{                            id2=true;                                   }                            }       }       function dian(){              var da = document.getElementsByTagName("input")[1];              var xiao = document.getElementsByTagName("input")[2];              var stop = document.getElementsByTagName("input")[3];              var kais = document.getElementsByTagName("input")[0];              ade(da,'click',function(){bd()});              ade(xiao,'click',function(){bx()});              ade(stop,'click',function(){tz()});              ade(kais,'click',function(){ks()});       }       function ade(a,b,c){                     if (a.addEventListener)                     {                     a.addEventListener(b,c,false)                     }else{                     a["on"+b] = c ;                     }              }              function ks(){                     if (ss)                     {                            clearInterval(ss);                     }                     ss = setInterval(pbft,10);                            }              function bd(){              if (qw<=200)              {                     qw++;                     this.div1.style.width = qw + "px";                     this.div1.style.height = qw + "px";                            clearTimeout(ge);                     gg = setTimeout(bd,20)              }                                   }              function bx(){              if (qw>50)              {                     qw--;                     this.div1.style.width = qw + "px";                     this.div1.style.height = qw + "px";                            clearTimeout(gg);                     ge = setTimeout(bx,20)              }                                          }              function tz(){                     clearInterval(ss);                     clearTimeout(gg);                     clearTimeout(ge);              }              dian();</script></html>

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