forprice.innerHTML=document.forms[0].elements[2].value;
我明白,forprice变量是改变(基本上左边的方程),但我不明白的是形式[0]部分 和元素[2]。价值的一部分 - 我对元素的理解。值部分是它取第二个位置的元素的值或可能的第二个元素的值。下列是为整个页面有人可以向我逐一解释这行代码:forprice.innerHTML = document.forms [0] .elements [2] .value;
代码-Thanks
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
<script>
var imgs=new Array();
imgs[0]=new Image(400,400);
imgs[1]=new Image(400,400);
imgs[2]=new Image(400,400);
imgs[3]=new Image(400,400);
imgs[4]=new Image(400,400);
imgs[0].src="m&p45blackwithcase.jpg";
//the above image does not load for some reason... i have tried changing the array order to included this first,
imgs[1].src="m&p45optimized.jpg";
imgs[2].src="m&p45blackoptimized.jpg";
//eliminated image due to corruption
imgs[3].src="taurus24-7package.jpg";
imgs[4].src="taurus689.jpg";
var imgs2=new Array();
imgs2[0]=new Image(400,400);
imgs2[1]=new Image(400,400);
imgs2[2]=new Image(400,400);
imgs2[0].src="ammochart.jpg";
imgs2[1].src="HANDGUN_AMMUNITION_CHART.jpg";
imgs2[2].src="rifle-ammo-chart-optimized.jpg";
</script>
<script>
var i=0;
function forward(){
// alert ("function");
i++;
if(i==5){
i=0;}
document.main.src=imgs[i].src;
}
function backward(){
i--;
if(i==-1){
i=4;}
document.main.src=imgs[i].src;
}
function update(form){
var imgvalue=document.getElementById("imgslider");
whichimg=imgvalue.value;
document.main.src=imgs[whichimg].src;}
function selectthis (form){
var cntr;
// alert ("function");
cntr=form.ammodd.selectedIndex-1;
document.main2.src=imgs2[cntr].src;
/*
//forprice=document.getElementById("desc");
//forprice.innerHTML=document.forms[0].elements[2].value;
removed because it's not needed
var imgvalue2=document.getElementById("secondary");
whichimg=imgvalue2.value;
document.secondary.src=imgs2[whichimg].src;
*/
}
var forprice;
var cntr;
function selectthis (form){
cntr=form.gundd.selectedIndex-1;
document.main.src=imgs[cntr].src;
forprice=document.getElementById("price");
forprice.innerHTML=document.forms[0].elements[2].value;
}
</script>
</head>
<body>
<div align="center">
<table width="600" border="0">
<caption>
<h1>Firearms Deluxe Emporium Superstore Outlet Market Discount Megacenter</h1>
</caption>
<tbody>
<tr>
<td><div align="center"><a href="home.html">Home</a></div></td>
<td><div align="center"><a href="products(image1works).html">Products</a></div></td>
<td><div align="center"><a href="checkout(toplayfunctionworks).html">Checkout</a></div></td>
</tr>
</tbody>
</table>
<h1> </h1>
<p><img src="m&p45blackwithcase.jpg" name="main" width="640" height="480" id="main"/></p>
<form id="form1" name="form1" method="post" action ="">
<p>Just </p>
<select name ="gundd" onchange="selectthis(this.form)">
<option value ="#" selected="selected"> Choose one </option>
<option value ="400.00">Psychedelic View 1</option>
<option value ="450.00">Psychedelic View 2</option>
<option value ="500.00">Psychedelic View 3</option>
<option value ="871.00">Psychedelic View 4</option>
</select>
<table width="400" border="4">
<tr>
<td align="right"> <input type="button" name="backup" id="backup" value="back" onclick="backward()"/></td>
<td align ="left"> <input type="button" name="forwardon" id="forwardon" value="forward" onClick="forward()"/></td>
</tr>
<tr>
<td colspan="2" align="center"> <input type="range" id="imgslider" name="imgslider" min="0" max="4" value="0" step="1" onchange="update(this.form)"></td>
</tr>
</table>
</form>
<form id="form2" name="form2" method="post" action ="">
<p> </p>
<p> </p>
<p> </p>
<p><img src="bullitsassorted-optimized.jpg" id="main2" name ="main2" width="620" height="465" alt=""/></p>
<p> We have all types of rounds available. </p>
<p>Whatever your needs are, we can fill them. </p>
<p>
<select name="ammodd" onchange="selectthis(this.form)">
<option selected="#">We even have amunition</option>
<option>Rifle Rounds</option>
<option>Handgun Rounds</option>
<option>Uses</option>
</select>
</form>
</div>
</body>
</html>
'forms [0]'指页面上的第一个表单,'elements [2]'指向该表单中的第三个元素。这些索引是从零开始的。 – j08691 2014-12-02 21:55:02
所以在这种情况下,我的第三个“元素”会是什么?(您的回答是我想的下一件事,但我不知道他们正在计算哪些元素 – Anonymous 2014-12-02 22:19:42
元素[]集合是指窗体中的窗体控件。在你的情况下,元素[2]引用onClick =“forward()”/>''input type =“button”name =“forwardon”id =“forwardon”value =“forward” 0] .elements [2] .value;'将是'forward'。 – j08691 2014-12-02 22:24:47