function BtnListener(){
var index=0;
var str="";
this.content=new Array();
this.="";
var element=document.getElementById("input-content"); //为什么在这里获取元素,不能在底下用;
this.inputNum=function(num){
content[index++]=num;
str=str+content[index-1]+", ";
element.value=str; //这里的element可能为null;为什么?
}
}
var index=0;
var str="";
this.content=new Array();
this.="";
var element=document.getElementById("input-content"); //为什么在这里获取元素,不能在底下用;
this.inputNum=function(num){
content[index++]=num;
str=str+content[index-1]+", ";
element.value=str; //这里的element可能为null;为什么?
}
}
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<input type="text" id="input-content" />
<script type="text/javascript">
(function BtnListener(){
var index=0;
var str="";
this.content=new Array();
this.="";
var element = document.getElementById("input-content"); this.inputNum = function(num){
content[index++] = num;
str = str + content[index-1] + ", ";
element.value=str;
};
this.inputNum(5);
})();
</script>
</body>
</html>
var element=document.getElementById("input-content").value;
element = str;
你可以判断str是否为空,若为空给一个默认的,飞空则给值