计算平方根.txt

来自「JavaScript特效（新）这里有许多的JAVA特效.供学者参考」· 文本 代码 · 共 26 行

<SCRIPT LANGUAGE="LiveScript">
<!-- Hide from old browsers
function Newton(Input){
   // f(x) = x*x - Input.value
   // f'(x) = 2*x
   var X = 1;
   var FX = X*X - Input.value;
   for (var i = 0; i < 10; i++) {
      X = X - FX/(2*X);
      FX = X*X - Input.value;
   }
   Input.value = X;
   return true;
}
function ClearForm(form) {
   form.Sqr.value = "";
}
<!-- done hiding from old browsers -->
</SCRIPT>
<CENTER><H1>平方根计算</H1>
<p>
<hr>
<b>
<FORM METHOD=POST>输入平方数:</b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><INPUT TYPE=TEXT NAME=Sqr SIZE=23 MAXLENGTH=10 onFocus="ClearForm(this.form)"></b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
<b><INPUT TYPE="button" VALUE="计算" onClick="Newton(this.form.Sqr)">
</FORM><BR CLEAR=ALL>