<html> <head> </head> <body> <script language="JavaScript"> <!-- var subcat = new Array(); subcat[0] = new Array('10','1','=1') subcat[1] = new Array('10','2','=2') subcat[2] = new Array('10','3','=3') subcat[3] = new Array('10','4','=4') subcat[4] = new Array('10','5','=5') subcat[5] = new Array('10','6','=6') subcat[6] = new Array('10','7','=7') subcat[7] = new Array('10','8','=8') subcat[8] = new Array('10','9','=9') subcat[9] = new Array('10','10','=10') subcat[10] = new Array('20','11','=11') subcat[11] = new Array('20','12','=12') subcat[12] = new Array('20','13','=13') subcat[13] = new Array('20','14','=14') subcat[14] = new Array('20','15','=15') subcat[15] = new Array('20','16','=16') subcat[16] = new Array('20','17','=17') subcat[17] = new Array('20','18','=18') subcat[18] = new Array('20','19','=19') subcat[19] = new Array('20','20','=20') function changeselect1(locationid) { document.form1.s2.length = 0; //初始化下拉列表 清空下拉数据 document.form1.s2.options[0] = new Option('==请选择==',''); //给第一个值 for (i=0; i<subcat.length; i++) //legth=20 { if (subcat[i][0] == locationid) //[0] [1] 第一列 第二列 {document.form1.s2.options[document.form1.s2.length] = new Option(subcat[i][1], subcat[i][2]);} //建立option //第一次 length=1 因为有==请选择== //i=9时 length= 10 值有11个 因为从0数起 subcat[i][0] == locationid屏蔽了再写 } } //--> </script>
<form name="form1"> 二级联动:
<select name="s1" onChange="changeselect1(this.value)"> <option>==请选择==</option> <option value="10">1-10</option> <option value="20">11-20</option> </select>
<select name="s2" onChange="alert(this.value)"> <option>==请选择==</option> </select>
</form> 
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