我正在尝试转换一个运行点击事件的JavaScript函数,以便在页面加载和窗口调整时启动。正如你在下面看到的,我注释掉了管理点击事件的部分,并添加了最后一行"window.onload",并手动将class="resizerd"添加到它正在处理的元素中。
该函数根本没有运行。Chrome的开发工具显示"Uncaught TypeError:无法设置未定义的属性'prevWidth'"我在哪里搞砸了语法吗?关于如何在加载时启动此功能,有什么建议吗?
谢谢!
//var clicked = document.getElementById("buttonImportant")
var resizeeContainer = document.getElementById('video_container');
var resizee = resizeeContainer.getElementsByTagName('video')[0];
/*clicked.addEventListener('click',function(){
if( resizeeContainer.className.lastIndexOf("resizerd")>=0 ){
}
else
{
resizeeContainer.className="resizerd";
}*/
myResizerObject.prevWidth = resizee.offsetWidth;
myResizerObject.prevHeight = resizee.offsetHeight;
myResizerObject.Init();
//},false);
myResizerObject.prevWidth = resizee.offsetWidth;
myResizerObject.prevHeight = resizee.offsetHeight;
myResizerObject.Init();
var RESIZER = function(){
this.prevWidth = resizee.offsetWidth;
this.prevHeight = resizee.offsetHeight;
this.resizee = resizeeContainer.getElementsByTagName('video')[0];
this.resizeeContainer = resizee.parentNode;
this.resizeeStyle = this.resizee.style;
var ratio = this.resizee.offsetHeight/this.resizee.offsetWidth;
var that = this;
this.Init = function(){
if( that.resizeeContainer.className.lastIndexOf("resizerd")>=0 )
{
var resizeeContOffsetWidth = that.resizeeContainer.offsetWidth;
var resizeeOffsetWidth = that.resizee.offsetWidth;
var resizeeContOffsetHeight = that.resizeeContainer.offsetHeight;
var resizeeOffsetHeight = that.resizee.offsetHeight;
if(that.prevWidth!= resizeeContOffsetWidth)
{
that.prevWidth = resizeeContOffsetWidth;
var desired = resizeeContainer.offsetHeight/resizeeContainer.offsetWidth;
if(desired>ratio){
that.resizeeStyle.width=resizeeContOffsetWidth*desired+resizeeContOffsetWidth*desired+"px";
that.resizeeStyle.left = -1*(resizeeOffsetWidth-resizeeContOffsetWidth)/2+'px';
}
else{
that.resizeeStyle.cssText="width:100%;height:auto;position:fixed;";
}
}
if(that.prevHeight!=resizeeContOffsetHeight)
{
that.prevHeight = resizeeContOffsetHeight;
var desired = resizeeContOffsetHeight/resizeeContOffsetWidth;
if(desired>ratio){ console.log(ratio);
//that.resizeeStyle.top = '0px';
that.resizeeStyle.left = -1*(resizeeOffsetWidth-resizeeContOffsetWidth)/2+'px';
that.resizeeStyle.width = resizeeContOffsetHeight*desired+resizeeContOffsetHeight/desired+'px';
}
else
{
that.resizeeStyle.top = -1*(resizeeOffsetHeight-resizeeContOffsetHeight)/2+'px';
}
}
}
};
};
var myResizerObject = new RESIZER();
window.onresize = myResizerObject.Init;
window.onload = myResizerObject.Init;
您是否尝试通过<body>
标记执行该函数?
类似:
<body onload="myfunction();">
尝试在页面正文的OnLoad="myfunction();"事件中调用整个resize javascript函数。每次加载页面时,我都会调整页面大小,而且效果很好。
您有这行:
myResizerObject.prevWidth = resizee.offsetWidth;
这可能是错误的原因。您没有对声明myResizerObject
做任何操作,因此它不能具有属性prevWidth
。
在下面的某个地方你做
var myResizerObject = new RESIZER();
我怀疑您希望这些行的顺序更合理:)
这样的代码应该可以正常工作:
var myResizerObject = new RESIZER();
function UpdateResizerObject() {
var resizeeContainer = document.getElementById('video_container');
var resizee = resizeeContainer.getElementsByTagName('video')[0];
myResizerObject.prevWidth = resizee.offsetWidth;
myResizerObject.prevHeight = resizee.offsetHeight;
myResizerObject.Init();
}
window.onload = function() {
UpdateResizerObject();
};
window.onresize = function() {
UpdateResizerObject();
};
不过,在定义了RESIZER
类之后就可以使用它了。
您的错误是在创建对象实例变量之前调用它。
编辑:一些基本调试。。向以下功能添加警报:
this.Init = function(){
alert("Init called.. container: " + that.resizeeContainer);
if (that.resizeeContainer)
alert("class: " + hat.resizeeContainer.className);
if( that.resizeeContainer.className.lastIndexOf("resizerd")>=0 )
{
...
}
}
看看你得到了什么。