JS 中全局变量和局部变量的有关问题
JS 中全局变量和局部变量的问题
可能是因为全局变量和局部变量定义问题,总是出错.
我的代码如下:
<html xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv= "content-type " content= "text/html; charset=utf-8 "/>
<title> Glider WPT </title>
<script type= "text/javascript ">
var LGMN = -6;
var LGMX = 37;
var LTMN = 30;
var LTMX = 50;
var ltn = new Array();
var ltx = new Array();
var lgn = new Array();
var lgx = new Array();
var latDelta = 5;
var lngDelta = 6;
var n = 0;
var m = 0;
function load(){
for(var i=LTMN; i <LTMX; i=i+latDelta){
ltn[n] = i;
ltx[n] = i+latDelta;
for(var j=LGMN; j <=LGMX; j=j+lngDelta){
lgn[m] = j;
lgx[m] = j+lngDelta;
m++;
}
n++;
}
alert(ltn.length); //------> 4 ????????????????????????
}
function affichager(){
document.write(ltn.length); //-------> 0 ???????????????????????
}
</script>
</head>
<body onload= "load() " onunload= "GUnload() ">
<?php
$k = ' <script type= "text/javascript "> affichager() </script> ';
echo $k;
?>
</body>
</html>
为什么两次输出的ltn.length(问号处)结果不一样呢? 怎样解决这个问题?
希望高手解答.
------解决方案--------------------
试试这个你就明白了:
<html xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv= "content-type " content= "text/html; charset=utf-8 "/>
<title> Glider WPT </title>
<script type= "text/javascript ">
var LGMN = -6;
var LGMX = 37;
var LTMN = 30;
var LTMX = 50;
var ltn = new Array();
var ltx = new Array();
var lgn = new Array();
var lgx = new Array();
var latDelta = 5;
var lngDelta = 6;
var n = 0;
var m = 0;
function load(){
for(var i=LTMN; i <LTMX; i=i+latDelta){
ltn[n] = i;
ltx[n] = i+latDelta;
for(var j=LGMN; j <=LGMX; j=j+lngDelta){
lgn[m] = j;
lgx[m] = j+lngDelta;
m++;
}
n++;
}
alert( "后赋值! "+ltn.length); //------> 4 ????????????????????????
}
function affichager(){
alert( "这里先执行! ");
document.write(ltn.length); //-------> 0 ???????????????????????
}
</script>
</head>
<body onload= "load() " onunload= "GUnload() ">
<?php
$k = ' <script type= "text/javascript "> affichager() </script> ';
echo $k;
?>
</body>
</html>
------解决方案--------------------
window.onload=function(){load();affichager();}
两个都放在onload事件中
可能是因为全局变量和局部变量定义问题,总是出错.
我的代码如下:
<html xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv= "content-type " content= "text/html; charset=utf-8 "/>
<title> Glider WPT </title>
<script type= "text/javascript ">
var LGMN = -6;
var LGMX = 37;
var LTMN = 30;
var LTMX = 50;
var ltn = new Array();
var ltx = new Array();
var lgn = new Array();
var lgx = new Array();
var latDelta = 5;
var lngDelta = 6;
var n = 0;
var m = 0;
function load(){
for(var i=LTMN; i <LTMX; i=i+latDelta){
ltn[n] = i;
ltx[n] = i+latDelta;
for(var j=LGMN; j <=LGMX; j=j+lngDelta){
lgn[m] = j;
lgx[m] = j+lngDelta;
m++;
}
n++;
}
alert(ltn.length); //------> 4 ????????????????????????
}
function affichager(){
document.write(ltn.length); //-------> 0 ???????????????????????
}
</script>
</head>
<body onload= "load() " onunload= "GUnload() ">
<?php
$k = ' <script type= "text/javascript "> affichager() </script> ';
echo $k;
?>
</body>
</html>
为什么两次输出的ltn.length(问号处)结果不一样呢? 怎样解决这个问题?
希望高手解答.
------解决方案--------------------
试试这个你就明白了:
<html xmlns= "http://www.w3.org/1999/xhtml ">
<head>
<meta http-equiv= "content-type " content= "text/html; charset=utf-8 "/>
<title> Glider WPT </title>
<script type= "text/javascript ">
var LGMN = -6;
var LGMX = 37;
var LTMN = 30;
var LTMX = 50;
var ltn = new Array();
var ltx = new Array();
var lgn = new Array();
var lgx = new Array();
var latDelta = 5;
var lngDelta = 6;
var n = 0;
var m = 0;
function load(){
for(var i=LTMN; i <LTMX; i=i+latDelta){
ltn[n] = i;
ltx[n] = i+latDelta;
for(var j=LGMN; j <=LGMX; j=j+lngDelta){
lgn[m] = j;
lgx[m] = j+lngDelta;
m++;
}
n++;
}
alert( "后赋值! "+ltn.length); //------> 4 ????????????????????????
}
function affichager(){
alert( "这里先执行! ");
document.write(ltn.length); //-------> 0 ???????????????????????
}
</script>
</head>
<body onload= "load() " onunload= "GUnload() ">
<?php
$k = ' <script type= "text/javascript "> affichager() </script> ';
echo $k;
?>
</body>
</html>
------解决方案--------------------
window.onload=function(){load();affichager();}
两个都放在onload事件中